feat(message): add comprehensive message system with database migrations and health checks

- Add database migrations for message base table with indexes for efficient querying
- Implement rich content support with attachment, embed, and poll tables
- Create social features including reactions, bookmarks, mentions, and read states
- Add thread management with participant tracking and resolution capabilities
- Include article posts with title, cover image, tags, and engagement metrics
- Support scheduled messages, stickers, forwards, and interactive components
- Fix UUID defaults and ensure proper uniqueness constraints for drafts
- Add gRPC health server for imks and health check client for appks connectivity
- Replace non-connectable 0.0.0.0 addresses with localhost in service discovery
- Normalize addresses during RPC configuration to handle bind address issues

migrate/000_message_base.sql

@@ -0,0 +1,46 @@
+-- ============================================================
+-- Migration: 000_message_base.sql
+-- Tables:  message
+-- ============================================================
+-- Core message table managed by imks. All companion tables
+-- (thread, attachment, embed, reaction, ...) reference message(id).
+
+BEGIN;
+
+CREATE TABLE IF NOT EXISTS message (
+    id                  UUID PRIMARY KEY,
+    channel_id          UUID NOT NULL,
+    author_id           UUID NOT NULL,
+    thread_id           UUID NULL,
+    reply_to_message_id UUID NULL REFERENCES message(id) ON DELETE SET NULL,
+    message_type        TEXT NOT NULL DEFAULT 'text',
+    body                TEXT NOT NULL,
+    metadata            JSONB NULL,
+    pinned              BOOLEAN NOT NULL DEFAULT FALSE,
+    system              BOOLEAN NOT NULL DEFAULT FALSE,
+    edited_at           TIMESTAMPTZ NULL,
+    deleted_at          TIMESTAMPTZ NULL,
+    created_at          TIMESTAMPTZ NOT NULL DEFAULT now(),
+    updated_at          TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+
+-- Cursor pagination: WHERE id < $cursor ORDER BY id DESC
+CREATE INDEX IF NOT EXISTS idx_message_channel_created
+    ON message (channel_id, created_at DESC);
+
+CREATE INDEX IF NOT EXISTS idx_message_author
+    ON message (author_id);
+
+CREATE INDEX IF NOT EXISTS idx_message_thread
+    ON message (thread_id)
+    WHERE thread_id IS NOT NULL;
+
+CREATE INDEX IF NOT EXISTS idx_message_reply_to
+    ON message (reply_to_message_id)
+    WHERE reply_to_message_id IS NOT NULL;
+
+CREATE INDEX IF NOT EXISTS idx_message_deleted
+    ON message (deleted_at)
+    WHERE deleted_at IS NOT NULL;
+
+COMMIT;