feat(plugins): plugin pages, per-user config, capabilities gate, mobile/telegram refactors

- Plugin HTTP routes + web pages (plugin-page-host, plugin-catalog, plugin-detail)
- Plugin access grants + per-user config (DB tables + API + frontend forms)
- Capabilities-based guard (caps.rs) replacing role-id checks
- Mobile connector: message routing, payload types, router refactor
- Telegram bot: auth flow, event handling improvements
- Honcho plugin: substantial rework
- Sidebar: plugin pages integration, role-driven visibility
- i18n: new strings for plugins, connectors, capabilities
- Remove unused mascot asset

web/i18n/en.js

@@ -16,6 +16,8 @@ export default {
   'nav.users':         'Users',
   'nav.roles':         'Roles',
   'nav.connectors':    'Connectors',
+  'nav.plugins':       'Plugins',
+  'nav.plugin_catalog': 'Plugin Catalog',
   'nav.catalog':       'Catalog',
   'nav.config':        'Settings',
   'nav.llm_requests':  'LLM Requests',
@@ -839,6 +841,45 @@ export default {
 
   'connectors.error.no_connector':    'No connector named "{name}" is available to you.',
 
+  // ── Plugins ─────────────────────────────────────────────────────────────────
+  'plugins.title':             'Plugins',
+  'plugins.loading':           'Loading…',
+  'plugins.section.mine':      'My plugins',
+  'plugins.section.manage':    'Manage plugins',
+  'plugins.empty.mine':        'No plugins available to you yet.',
+  'plugins.empty.ask_admin':   'Ask an admin to grant you access.',
+  'plugins.empty.manage':      'No plugins registered.',
+  'plugins.status.active':     'active',
+  'plugins.status.running':    'running',
+  'plugins.status.enabled':    'enabled',
+  'plugins.status.off':        'off',
+  'plugins.enabled':           'Enabled',
+  'plugins.save':              'Save',
+  'plugins.save_config':       'Save config',
+  'plugins.saved':             'Saved.',
+  'plugin_page.loading':       'Loading…',
+  'plugin_page.unavailable':   'This page is not available (plugin disabled or page not granted).',
+  'plugins.yes':               'yes',
+  'plugins.no':                'no',
+  'plugins.badge.user_config': 'per-user settings',
+  'plugins.access.btn':        'User access',
+  'plugins.access.desc':       'Tick a box to let that person see and configure this plugin. Saving replaces the whole list.',
+  'plugins.access.empty':      'No users.',
+  'plugins.access.save':       'Save access',
+  'plugins.error.required':    '"{field}" is required.',
+  'plugins.catalog.title':     'Plugin Catalog',
+  'plugins.catalog.configure': 'Configure',
+  'plugins.health.ok':           'active',
+  'plugins.health.off':          'off',
+  'plugins.health.needs_config': 'needs configuration',
+  'plugins.health.not_running':  'not running',
+  'plugins.badge.instance_config': 'instance settings',
+  'plugins.detail.back':         'Back to catalog',
+  'plugins.detail.config.title': 'Instance configuration',
+  'plugins.detail.config.empty': 'This plugin has no instance settings.',
+  'plugins.detail.access.title': 'User access',
+  'plugins.detail.not_found':    'No plugin named "{id}".',
+
   // ── Providers ───────────────────────────────────────────────────────────────
   'providers.title':              'Providers',
   'providers.add':                'Add',