refactor(channels): make built-in channels self-contained (#4908)

* refactor(channels): own setup and instance contracts

* refactor(channels): isolate management contracts

* refactor(channels): normalize activation contracts

* fix(channels): enforce management contracts

* refactor(channels): finish setup ownership migration

* fix(channels): harden management contracts

* fix(channels): enforce lazy loading and runtime ownership

* fix(feishu): make multi-instance startup idempotent

* fix(webui): render channel setup contracts cleanly

* fix(feishu): stop websocket clients cleanly

* fix(channels): enforce persistence and activation gates

* fix(channels): preserve global feature action scope

* fix(channels): apply defaults for single plugins

* fix(channels): enforce management contract boundaries

* refactor(feishu): remove identity helper indirection

* fix(channels): preserve management setup contracts

* refactor(channels): generalize instance settings UI

* refactor(channels): package channel plugins with web UI metadata

* refactor(channels): make built-ins self-contained packages

* test(channels): colocate tests with channel packages

* fix(dingtalk): use official brand icon

* feat(channels): colocate webui translations

* docs(channels): clarify plugin ownership

* test(exec): remove output wait race

* refactor(channels): unify plugin descriptors

* fix(channels): enforce descriptor-owned contracts

* refactor(channels): finish package-owned plugin setup

* refactor(channels): use repository-owned packages only

* fix(channels): self-describe dependencies and runtime state

* fix(channels): warn about legacy entry points

webui/src/i18n/locales/en/common.json

@@ -510,7 +510,7 @@
     },
     "channels": {
       "description": "Connect chat apps, email, and WebUI to nanobot.",
-      "caption": "{{enabled}} enabled · {{total}} channels",
+      "caption": "{{enabled}} running · {{total}} channels",
       "searchPlaceholder": "Search channels",
       "backToChannels": "All channels",
       "catalog": "Channels",
@@ -527,13 +527,51 @@
       "needsConfig": "Needs setup",
       "connect": "Connect",
       "reconnect": "Reconnect",
-      "feishuQrAlt": "Feishu connection QR code",
-      "feishuScanTitle": "Scan with Feishu",
-      "feishuScanDescription": "Use Feishu or Lark on your phone to scan this code. nanobot will finish setup automatically after authorization.",
-      "feishuWaiting": "Waiting for authorization...",
-      "feishuConnected": "Feishu is connected.",
-      "feishuConnectStopped": "Connection stopped.",
-      "feishuConnecting": "Connecting..."
+      "advanced": "Advanced",
+      "checkAndEnable": "Check and enable",
+      "checkConnection": "Check connection",
+      "checkedAndEnabled": "Checked and enabled.",
+      "checking": "Checking...",
+      "checkOnly": "Check only",
+      "commandCopied": "Command copied.",
+      "commandCopyFailed": "Could not copy command.",
+      "configuredInstances": "{{count}} instances configured",
+      "connectPreview": "The in-browser connect flow is next. For now, run the command below.",
+      "copyCommand": "Copy command",
+      "filterAll": "All",
+      "filterOff": "Not running",
+      "filterOn": "Running",
+      "helperCopied": "{{name}} copied.",
+      "helperCopyFailed": "Could not copy {{name}}.",
+      "hideSecret": "Hide secret",
+      "instanceConfigured": "Configured",
+      "instanceNeedsSetup": "Needs setup",
+      "runtimeFailed": "Failed",
+      "runtimeStarting": "Starting",
+      "runtimeStopped": "Not running",
+      "managedByWebui": "Managed by WebUI",
+      "officialGuide": "Official guide",
+      "optional": "Optional",
+      "providerPreset": "Provider",
+      "requiredSetup": "Required setup",
+      "savedSecret": "Saved",
+      "savedSecretPlaceholder": "Saved secret",
+      "savedSettings": "Saved settings.",
+      "saveSettings": "Save settings",
+      "selectChannel": "View {{name}} settings",
+      "setupSteps": "Next steps",
+      "showSecret": "Show secret",
+      "toggleChannel": "{{name}} channel",
+      "toggleInstance": "{{name}} instance",
+      "tryIt": "Try it",
+      "validationFailed": "Check the required setup before enabling.",
+      "validation": {
+        "connected": "Connected",
+        "configured": "Configured manually",
+        "needs_setup": "Needs setup",
+        "invalid": "Invalid",
+        "unsupported": "Manual setup"
+      }
     },
     "nanobotFeatures": {
       "enabled": "Enabled",