fix(db): make earliest migrations idempotent (0002/0011/0012)

[jonathonbyrdziak]

Turns fully-specced but never-shipped autonomous-cycle issue #486 into a PR.

Problem

DatabaseManager.runMigrations fails fast — any error in a migration's up SQL is rethrown and aborts DB init (DatabaseManager.ts:138). Migrations 0002, 0011, 0012 are the earliest and predate the IF NOT EXISTS convention that every migration from 0009 onward already follows.

On any install where the tables/columns already exist but aren't recorded in sulla_migrations (pre-tracking installs, restored DBs, a manually seeded migration table), these three re-run their up and throw 42P07 (duplicate table) / duplicate column — bricking boot.

Fix

• 0002 — CREATE TABLE agent_awareness → CREATE TABLE IF NOT EXISTS
• 0011 — CREATE TABLE sulla_settings → CREATE TABLE IF NOT EXISTS; also fixes a latent down-migration bug — it dropped settings instead of sulla_settings
• 0012 — ADD COLUMN "cast" → ADD COLUMN IF NOT EXISTS; down → DROP COLUMN IF EXISTS

Audit

Swept all 22 registered migrations: these three are the only non-idempotent DDL. 0009/0014/0024 already use ADD COLUMN IF NOT EXISTS; 0010 indexes use CREATE INDEX IF NOT EXISTS; no CREATE TYPE/enum. Schema-only, no user data (complies with the no-user-data-in-migrations rule).

Verification (this PR)

• tsc --noEmit --isolatedModules exit 0 — template literals balanced.
• Confirmed against the live DB that agent_awareness, sulla_settings, and the sulla_settings."cast" column all already exist (the exact bricking precondition).
• Ran all three fixed up statements against that live DB → all succeed as no-ops (0 rows affected). Pre-fix these would have thrown. Idempotency proven.

Diff: 3 files, +6 −6.

Closes #486

🤖 Generated with Claude Code during an autonomous heartbeat cycle.