feat(l10n): translate manual unit pages (FR/RO)

Localize the 51 in-game manual unit detail pages (Templates/Manual/1*.tpl,
typ=1) so they render in the player's language instead of English, continuing
the manual l10n started in the building pages PR.

What changed:
- 51 unit pages (Romans/Teutons/Gauls/Nature/Natars) now use translation
  constants for every hardcoded string: tribe tags -> TRIBE1..5, the stat
  labels (attack value, defence vs infantry/cavalry, Velocity, fields/hour,
  Can carry, Duration of training), the unit descriptions, the NPC reference
  notes and the "forward" nav.
- 48 new constants added to en/fr/ro:
  * 7 shared stat labels (MANUAL_ATTACK_VALUE, MANUAL_DEF_INFANTRY,
    MANUAL_DEF_CAVALRY, MANUAL_VELOCITY, MANUAL_FIELDS_HOUR, MANUAL_CAN_CARRY,
    MANUAL_TRAINING_DURATION)
  * 2 NPC reference notes (MANUAL_NPC_NATARS, MANUAL_NPC_NATURE)
  * 1 templated Nature-animal blurb (MANUAL_UDESC_ANIMAL_EXP, used via
    printf with the animal name + xp value, so the 10 animal pages share it)
  * 38 unit descriptions (MANUAL_UDESC_*). Identical descriptions are shared:
    settlers (110/120/130) and rams (117/127) reuse one constant each.
- Reuses constants already present upstream and in the building pages branch:
  TRIBE1..5, LEVEL, FORWARD, CROP_CONSUMPTION, PREREQUISITES, UPKEEP, DURATION,
  RESOURCES, U1..U50.

English render is unchanged: the English constant values are the existing page
text extracted verbatim (whitespace-collapsed). it/zh are intentionally left to
fall back to English via the en.php fallback wired up earlier.

Scope note: this builds on the manual building-pages l10n branch (reuses
CROP_CONSUMPTION). The 17 "new features" pages (typ=11/13) are out of scope and
will be a follow-up PR. RO strings are functional but would benefit from a
native review.

GameEngine/Lang/en.php

@@ -2406,6 +2406,54 @@ tz_def('MANUAL_DESC_WONDER', "The wonder of the world represents the pride of cr
 tz_def('MANUAL_DESC_HORSEDRINKING', "The horse drinking trough cares for the wellbeing of your horses and therefore also increases the speed of their training.<br /><br />The horse drinking trough reduces the crop usage by one for the following soldiers: Equites Legati from level 10, Equites Imperatoris from level 15 and Equites Caesaris from level 20.<br /><br />The horse drinking trough can only be built by Romans.");
 tz_def('MANUAL_DESC_GREATWORKSHOP', "In the great workshop siege engines like catapults and rams can be built, albeit at triple the cost of a standard unit. The higher its level the faster units are produced.<br /><br />It cannot be built in the capital.");
 
+tz_def('MANUAL_ATTACK_VALUE', "attack value");
+tz_def('MANUAL_DEF_INFANTRY', "defence against infantry");
+tz_def('MANUAL_DEF_CAVALRY', "defence against cavalry");
+tz_def('MANUAL_VELOCITY', "Velocity");
+tz_def('MANUAL_FIELDS_HOUR', "fields/hour");
+tz_def('MANUAL_CAN_CARRY', "Can carry");
+tz_def('MANUAL_TRAINING_DURATION', "Duration of training");
+tz_def('MANUAL_NPC_NATARS', "Description is intended for reference only. The Natars are a pure NPC tribe and thus cannot be played by oneself.");
+tz_def('MANUAL_NPC_NATURE', "Description is intended for reference only. The Nature are a pure NPC tribe and thus cannot be played by oneself.");
+tz_def('MANUAL_UDESC_ANIMAL_EXP', "The experience a hero gains by killing an animal is determined by the upkeep the animal needed. This means a %s will give just %d experience point.");
+tz_def('MANUAL_UDESC_1', "The Legionnaire is the simple and all-purpose infantry of the Roman Empire. With his well-rounded training, he is good at both defence and attack. However, the Legionnaire will never reach the levels of the more specialized troops.");
+tz_def('MANUAL_UDESC_2', "The Praetorians are the emperor's guard and they defend him with their life. Because their training is specialized for defence, they are very weak attackers.");
+tz_def('MANUAL_UDESC_3', "The Imperian is the ultimate attacker of the Roman Empire. He is quick, strong, and the nightmare of all defenders. However, his training is expensive and time-intensive.");
+tz_def('MANUAL_UDESC_4', "The Equites Legati are the roman reconnaissance troops. They are pretty fast and can spy on enemy villages in order to see resources and troops. <br /><br /> If there are no Scouts, Equites Legati or Pathfinders in the scouted village, the scouting remains unnoticed.");
+tz_def('MANUAL_UDESC_5', "The Equites Imperatoris are the standard cavalry of the roman army and are very well armed. They are not the fastest troops, but are a horror for unprepared enemies. You should, however, always keep in mind that catering for horse and rider isn't cheap.");
+tz_def('MANUAL_UDESC_6', "The Equites Caesaris are the heavy cavalry of Rome. They are very well armoured and deal great amounts of damage, but all that armour and weaponry comes with a price. They are slow, carry less resources and feeding them is expensive.");
+tz_def('MANUAL_UDESC_7', "The Battering Ram is a heavy support weapon for your infantry and cavalry. Its task is to destroy the enemy walls and therefore increase your troops’ chances of overcoming the enemy's fortifications.");
+tz_def('MANUAL_UDESC_8', "The Catapult is an excellent long-distance weapon; it is used to destroy the fields and buildings of enemy villages. However, without escorting troops it is almost defenceless so don't forget to send some of your troops with it. <br /><br /> Having a high level rally point makes your catapults more accurate and gives you the option to target additional enemy buildings. With a level 10 rally point each building except for the cranny, stonemason's lodge and trapper can be targeted. <br /> HINT: Fire catapults CAN hit the cranny, trappers or stonemason's lodge when they target randomly.");
+tz_def('MANUAL_UDESC_9', "The Senator is the tribe's chosen leader. He's a good speaker and knows how to convince others. He is able to persuade other villages to fight with the empire. <br /><br /> Every time the Senator speaks to the inhabitants of a village the enemy's loyalty value decreases until the village is yours.");
+tz_def('MANUAL_UDESC_10', "Settlers are brave and daring citizens who move out of the village after a long training session to found a new village in your honour. <br /><br /> As the journey and the founding of the new village are very difficult, three settlers are bound to stick together. They need a basis of 750 units per resource.");
+tz_def('MANUAL_UDESC_11', "Clubswingers are the cheapest unit in Travian. They are quickly trained and have medium attack capabilities but their armour isn’t the best. Clubswingers are almost defenceless against cavalry and will be ridden down with ease.");
+tz_def('MANUAL_UDESC_12', "In the Teuton army the Spearman’s task is defence. He is especially good against cavalry thanks to his weapons length. <br /><br /> However, don't use him as an attacking unit because his offensive capabilities are very low.");
+tz_def('MANUAL_UDESC_13', "This is the Teuton's strongest infantry unit. He is strong at both offence and defence but he is slower and more expensive than other units.");
+tz_def('MANUAL_UDESC_14', "The Scout moves far ahead of the Teuton troops in order to get an impression of the enemy's strength and his villages. He moves on foot, which makes him slower than his Roman or Gaul counterparts. He scouts the enemy units, resources and fortifications. <br /><br /> If there are no enemy Scouts, Pathfinders or Equites Legati in the scouted village then the scouting remains unnoticed.");
+tz_def('MANUAL_UDESC_15', "As they are equipped with heavy armour Paladins are a great defensive unit. Infantry will find it especially hard to get through his shield. <br /><br /> Unfortunately their attacking capabilities are rather low and their speed, compared to other cavalry units, is below the average. Their training takes very long and is rather expensive..");
+tz_def('MANUAL_UDESC_16', "The Teutonic Knight is a formidable warrior and brings fear and despair over his foes. In defence he stands out against enemy cavalry. However, the cost of training and feeding him is extraordinary.");
+tz_def('MANUAL_UDESC_17', "The Ram is a heavy support weapon for your infantry and cavalry. Its task is to destroy the enemy walls and therefore increase your troops’ chances of overcoming the enemy's fortifications.");
+tz_def('MANUAL_UDESC_18', "The Catapult is an excellent long-distance weapon; it is used to destroy the fields and buildings of enemy villages. However, without escorting troops it is almost defenceless so don't forget to send some of your troops with it. <br /><br /> Having a high level rally point makes your catapults more accurate and gives you the option to target additional enemy buildings. With a level 10 rally point each building except for the cranny, stonemason's lodge and trapper can be targeted. <br /> HINT: Catapults CAN hit the cranny, trappers or stonemason's lodges when they target randomly.");
+tz_def('MANUAL_UDESC_19', "Out of their midst the Teutons choose their Chief. To be chosen, bravery and strategy aren't enough; you also have to be a formidable speaker as it is the Chief's primary objective to convince the population of foreign villages to join the Chief's tribe. <br /><br /> The more often the Chief speaks to the population of a village the more the loyalty of the village sinks until it finally joins the chief's tribe.");
+tz_def('MANUAL_UDESC_21', "As they are infantry, the Phalanx is cheap and fast to produce. <br /><br /> Though their attack power is low, in defence they are quite strong against both infantry and cavalry.");
+tz_def('MANUAL_UDESC_22', "The Swordsmen are more expensive than the Phalanx, but they are an attacking unit. <br /><br /> Defensively they are quite weak, especially against cavalry.");
+tz_def('MANUAL_UDESC_23', "The Pathfinder is the Gaul's reconnaissance unit. They are very fast and they can carefully advance on the enemy units, resources or buildings to spy on them. <br /><br /> If there aren't any Scouts, Equites Legati or Pathfinders in the scouted village, the scouting remains unnoticed.");
+tz_def('MANUAL_UDESC_24', "Theutates Thunders are very fast and powerful cavalry units. They can carry a large amount of resources which makes them excellent raiders too. <br /><br /> In defence their abilities are average at best.");
+tz_def('MANUAL_UDESC_25', "This medium cavalry unit is brilliant at defence. The main purpose of the Druidrider is to defend against enemy infantry. Its costs and supply are relatively expensive.");
+tz_def('MANUAL_UDESC_26', "The Haeduans are the Gaul's ultimate weapon for attacking and defending against cavalry. Few can match them in these points. <br /><br /> However, their training and equipment is also very expensive. They eat 3 units of crop per hour so you should think very carefully if they will be worth it.");
+tz_def('MANUAL_UDESC_28', "The Trebuchet is an excellent long-distance weapon; it is used to destroy the fields and buildings of enemy villages. However, without escorting troops it is almost defenceless so don't forget to send some of your troops with it. <br /><br /> Having a high level rally point makes your catapults more accurate and gives you the option to target additional enemy buildings. With a level 10 rally point each building except for the cranny, stonemason's lodges and trapper can be targeted. <br /> HINT: The Trebuchet CAN hit the cranny, trappers or stonemason's lodges when it targets randomly.");
+tz_def('MANUAL_UDESC_29', "Each tribe has an ancient and experienced fighter whose presence and speeches are able to convince the population of enemy villages to join his tribe. <br /><br /> The more often the Chieftain speaks in front of the walls of an enemy village the more its loyalty sinks until it joins the Chieftain's tribe.");
+tz_def('MANUAL_UDESC_31', "Rats are cheap and breed really fast but can't carry much.<br /><br />This is probably the cheapest of the nature units and the ugliest.");
+tz_def('MANUAL_UDESC_44', "The Natars use flocks of birds to gather intelligence about their enemies. Thanks to the advantage of scouting from the air, it is almost impossible to stop the Natarian scouting squads; on the other hand, even a simple-minded villager can easily notice the screeching and feathered flocks.");
+tz_def('MANUAL_UDESC_41', "Their long and pointed pikes are used as the main line of defence in any battle. The Natarian Pikemen are bold and daring warriors who use their dexterity to quickly down enemy horsemen and finish them off.");
+tz_def('MANUAL_UDESC_42', "The thorn-like extensions on their helmets, bracers and shoulder-parts of their armour give the Thorned Warriors their name. The men who fight for the Natars as Thorned Warriors are persistent and well trained, offering a bloody battle to anyone who is foolish enough to attack them.");
+tz_def('MANUAL_UDESC_43', "Adored by their people and feared by their enemies, a Guardsman fights without a mount but is nevertheless one of the most valuable soldiers in the Natarian army, thanks to his versatility. They are deemed as well trained fighters, leaving their enemies with almost no chances to win. Due to their heavy armour, they can be used as strong and reliable defence troops too.");
+tz_def('MANUAL_UDESC_45', "It smells only of death and decay when the Axeriders saddle up and prepare to go to war. As skillfully as a farmer uses his scythe to reap, an Axerider swings his mighty blade. A single blow is normally sufficient to behead an opponent and make the bystanders cry out in anguish.");
+tz_def('MANUAL_UDESC_46', "Only the most skilful and strongest warriors of the Natars survive the training to become a Natarian Knight. Seeing them fight fills one with awe and shows what true warfare is. They wield their blades as if they were one with their arms and hands and use their shields seemingly as a natural extension of their bodies. Even the horses they ride are specially bred and trained - no normal horse would be able to wear the armour the knights' horses wear, let alone the knight himself, and still be able to go to war. Whispers of their glory have even reached the most distant kingdoms, spreading fear and horror.");
+tz_def('MANUAL_UDESC_47', "No other tribe but the Natars knows how to use these impressive creatures for their purposes. Neither a wall nor a palisade can withstand the War elephant’s attacks. A walking killing machine, trampling down anything that tries to oppose it or tries to come its way.");
+tz_def('MANUAL_UDESC_48', "Even as engineers, the Natars were very successful. They created machinery of war long before anyone else and have since then perfected it in every way. The Ballista, a huge crossbow-like weapon, fires its projectiles with such a force that no wall or shield can deflect them. When the engineers dismantle it to move it to the next battlefield, here is usually nothing but ruins left where the projectiles hit.");
+tz_def('MANUAL_UDESC_49', "A mixture of pure fear, admiration and awe moves the villagers when the Natarian Emperor speaks to them. This commanding and well outfitted figure is fully aware of his effect on others and knows how to subjugate an entire village with a single harangue.");
+tz_def('MANUAL_UDESC_50', "Daring journeymen and master builders, driven by zest for action and knowing every little secret about cultivating land, building Palaces and fortifying villages, the Natarian Settlers go out in parties of three to claim land in the name of their Natarian lords.");
 // ===== display-time localization of stored report topics =====
 // Reports are generated server-side at battle resolution and stored in the DB
 // (column `topic`) with English connectors. This rewrites them to the viewing