Add remote routing URL support (#6168)

* Add remote routing URL support

* Harden remote routing refresh

* fix(sub): harden remote routing fetch and accept Mihomo src rule flag

Remote routing bytes reach the YAML/JSON parsers from goroutines that run
outside Gin's recovery, so a parser panic on crafted input would take down
the whole panel. Contain it in fetch() (a panic now degrades to a failed
refresh that keeps the last-good value and releases the in-flight slot)
and start the refresh, cache-load and startup-warm goroutines through
common.GoRecover like the other background workers.

The route-graph validator only skipped a trailing no-resolve flag, so a
valid Mihomo rule like IP-CIDR,x,DIRECT,no-resolve,src was rejected as an
unknown target; skip both option flags.

Also deduplicate the HTTPS-source classification into
common.ParseRemoteRoutingURL so the save-time validator and the resolver
can never drift (internal/sub imports internal/web/service, so the copy
existed only to avoid the import cycle), move the test-only
mergeRemoteClashRulesYAML helper into the test file, and trim oversized
comment blocks.

---------

Co-authored-by: Duxxie <yelloduxx@users.noreply.github.com>
Co-authored-by: Sanaei <ho3ein.sanaei@gmail.com>

internal/web/cadence_test.go

@@ -23,6 +23,7 @@ func TestJobCadencesAreValidCronSpecs(t *testing.T) {
 		"cadenceNodeHeartbeat": cadenceNodeHeartbeat,
 		"cadenceNodeTraffic":   cadenceNodeTraffic,
 		"cadenceOutboundSub":   cadenceOutboundSub,
+		"cadenceRemoteRouting": cadenceRemoteRouting,
 		"cadenceCheckHash":     cadenceCheckHash,
 		"cadenceCPUAlarm":      cadenceCPUAlarm,
 	}