Feat: bot message routing (#2100)

* refactor: pipeline routing rules - add routed_by_rule bypass and diagnostic logging

- Add routing rules editor (RoutingRulesEditor component)
- Add routed_by_rule bypass logic in response rules
- Add diagnostic logging for pipeline routing
- Database migration for bot pipeline routing rules
- Extract RoutingRulesEditor component from BotForm
- Revert log levels to debug

* feat: add message_has_element routing rule type

Support routing by message element type (Image, Voice, File, Forward,
Face, At, AtAll, Quote) with eq/neq operators.

* test: add unit tests for pipeline routing rules

20 tests covering _match_operator (eq/neq/contains/not_contains/
starts_with/regex/invalid) and resolve_pipeline_uuid (launcher_type/
launcher_id/message_content/message_has_element/first-match-wins/
skip-invalid/default-operator).

* fix(web): add missing 'message_has_element' to routing rule type validation

The Zod schema and TypeScript type for PipelineRoutingRule.type were
missing the 'message_has_element' variant, causing silent form validation
failure when saving routing rules with this type.

* feat: add pipeline discard functionality and localization support

* feat(web): improve drag-and-drop with DragOverlay, add discard monitoring and pipeline icons

- Add DragOverlay for smooth cursor-following drag in routing rules editor
- Remove transition to eliminate redundant swap animation on drop
- Record discarded messages in monitoring system via _record_discarded_message
- Display pipeline name (Workflow icon) and runner name (Play icon) on session monitor messages
- Show discard badge on discarded messages in session monitor
- Add i18n translations for discarded/userMessage/botMessage

* fix: ensure discarded messages appear in session monitor and improve icons

- Create/update monitoring session for discarded messages so they show in
  the bot session monitor (was only inserting message rows, not sessions)
- Use human-readable 'Discarded' as pipeline_name instead of '__discard__'
- Change runner icon from Play to Bot for better AI Agent semantics

* fix: merge discarded messages into same session and remove session-level pipeline name

- Use LauncherTypes enum for session_id in discarded messages to match
  the format used by monitoring_helper (fixes duplicate sessions)
- Don't overwrite session pipeline info on discard — a session can have
  messages from multiple pipelines
- Remove pipeline_name from session list and chat header since it's
  now shown per-message and a session is no longer single-pipeline

* fix(web): only show save button on config tab in bot detail page

* fix(web): scroll to bottom after messages render in session monitor

---------

Co-authored-by: RockChinQ <rockchinq@gmail.com>

web/src/i18n/locales/en-US.ts

@@ -307,6 +307,39 @@ const enUS = {
     routingConnection: 'Routing & Connection',
     routingConnectionDescription:
       'Bind the pipeline that processes messages for this bot',
+    routingRules: 'Conditional Routing Rules',
+    routingRulesDescription:
+      'Rules are evaluated in order; first match routes to its pipeline. Fallback to the default pipeline above if none match.',
+    addRoutingRule: 'Add Rule',
+    ruleTypeLauncherType: 'Session Type',
+    ruleTypeLauncherId: 'Session ID',
+    ruleTypeMessageContent: 'Message Content',
+    operatorEq: 'Equals',
+    operatorNeq: 'Not Equals',
+    operatorContains: 'Contains',
+    operatorNotContains: 'Not Contains',
+    operatorStartsWith: 'Starts With',
+    operatorRegex: 'Regex',
+    operatorHas: 'Has',
+    operatorNotHas: 'Does not have',
+    ruleTypeMessageHasElement: 'Message Element',
+    ruleValueElementPlaceholder: 'Select element type',
+    elementImage: 'Image',
+    elementVoice: 'Voice',
+    elementFile: 'File',
+    elementForward: 'Forward',
+    elementFace: 'Emoji',
+    elementAt: '@Mention',
+    elementAtAll: '@All',
+    elementQuote: 'Quote',
+    ruleValuePlaceholder: 'Match value',
+    ruleValueLauncherIdPlaceholder: 'Group or user ID',
+    ruleValueMessagePlaceholder: 'Message text',
+    ruleValuePrefixPlaceholder: 'e.g. !draw',
+    ruleValueRegexpPlaceholder: 'e.g. ^/help',
+    pipelineDiscard: 'Discard Message',
+    sessionTypePerson: 'Private Chat',
+    sessionTypeGroup: 'Group Chat',
     adapterConfigDescription: 'Configure the selected platform adapter',
     dangerZone: 'Danger Zone',
     dangerZoneDescription: 'Irreversible and destructive actions',
@@ -355,6 +388,9 @@ const enUS = {
       refresh: 'Refresh',
       active: 'Active',
       inactive: 'Inactive',
+      discarded: 'Discarded',
+      userMessage: 'User',
+      botMessage: 'Assistant',
     },
   },
   plugins: {