feat(aircoding): AirCoding V2 baseline — deterministic multi-agent architecture

Forked from OpenCode v1.17.4 with multi-agent system:
- 5 agents: aircoding, scheduler, worker, architect, reviewer
- Deterministic DAG scheduling engine (coordinator_tick)
- Tool whitelists as hard enforcement
- AirCoding validation plugin
- System prompt injection for routing
- V1 requirements: C4 docs, ADR, AGENTS.md, debug-log.md
- Design documents in docs/

packages/core/migration/20260427172553_slow_nightmare/migration.sql

@@ -0,0 +1,17 @@
+CREATE TABLE `session_message` (
+	`id` text PRIMARY KEY,
+	`session_id` text NOT NULL,
+	`type` text NOT NULL,
+	`time_created` integer NOT NULL,
+	`time_updated` integer NOT NULL,
+	`data` text NOT NULL,
+	CONSTRAINT `fk_session_message_session_id_session_id_fk` FOREIGN KEY (`session_id`) REFERENCES `session`(`id`) ON DELETE CASCADE
+);
+--> statement-breakpoint
+DROP INDEX IF EXISTS `session_entry_session_idx`;--> statement-breakpoint
+DROP INDEX IF EXISTS `session_entry_session_type_idx`;--> statement-breakpoint
+DROP INDEX IF EXISTS `session_entry_time_created_idx`;--> statement-breakpoint
+CREATE INDEX `session_message_session_idx` ON `session_message` (`session_id`);--> statement-breakpoint
+CREATE INDEX `session_message_session_type_idx` ON `session_message` (`session_id`,`type`);--> statement-breakpoint
+CREATE INDEX `session_message_time_created_idx` ON `session_message` (`time_created`);--> statement-breakpoint
+DROP TABLE `session_entry`;