feat: add Planka service provider with full notification and command support

Webhook-based provider for Planka (self-hosted Kanban board) with:
- 15 event types (cards, boards, lists, comments, tasks, attachments, labels)
- Bearer token webhook authentication
- Async API client for boards/cards/lists
- 30 notification templates (en/ru) + 26 command templates (en/ru)
- Bot commands: /status, /boards, /cards, /lists
- Default tracking config, template config, command config seeded on startup
- DB migration for 15 new tracking_config columns
- Frontend: provider config UI with auto-name, Planka-specific hints
- Frontend: tracking config event toggles for all 15 Planka events

frontend/src/lib/i18n/en.json

@@ -107,6 +107,7 @@
 		"checking": "Checking...",
 		"typeImmich": "Immich",
 		"typeGitea": "Gitea",
+		"typePlanka": "Planka",
 		"typeScheduler": "Scheduler",
 		"loadError": "Failed to load providers.",
 		"externalDomain": "External Domain",
@@ -116,6 +117,9 @@
 		"webhookSecret": "Webhook Secret",
 		"webhookSecretKeep": "Webhook Secret (leave empty to keep current)",
 		"webhookSecretHint": "Shared secret for HMAC-SHA256 signature verification. Set the same secret in Gitea webhook settings.",
+		"plankaWebhookSecretHint": "Bearer token for webhook authentication. Set the same token as WEBHOOK_ACCESS_TOKEN in Planka.",
+		"plankaApiKeyHint": "Optional. Needed for connection testing and board listing.",
+		"plankaWebhookUrlHint": "Set this as the Webhook URL in Planka environment config (relative to your bridge host).",
 		"webhookSecretRequired": "Webhook secret is required",
 		"apiToken": "API Token",
 		"apiTokenHint": "Optional. Needed for connection testing and repository listing.",
@@ -378,6 +382,21 @@
 		"prMerged": "PR merged",
 		"prCommented": "PR commented",
 		"releasePublished": "Release published",
+		"cardCreated": "Card created",
+		"cardUpdated": "Card updated",
+		"cardMoved": "Card moved",
+		"cardDeleted": "Card deleted",
+		"cardCommented": "Card commented",
+		"commentUpdated": "Comment updated",
+		"boardCreated": "Board created",
+		"boardUpdated": "Board updated",
+		"boardDeleted": "Board deleted",
+		"listCreated": "List created",
+		"listUpdated": "List updated",
+		"listDeleted": "List deleted",
+		"attachmentCreated": "Attachment added",
+		"cardLabelAdded": "Label added",
+		"taskCompleted": "Task completed",
 		"scheduledMessage": "Scheduled message",
 		"trackImages": "Track images",
 		"trackVideos": "Track videos",
@@ -795,6 +814,7 @@
 		"previewWebhook": "Preview as plain text",
 		"providerImmich": "Self-hosted photo server",
 		"providerGitea": "Self-hosted Git service",
+		"providerPlanka": "Self-hosted Kanban board",
 		"providerScheduler": "Time-based scheduled messages"
 	},
 	"error": {