chore(meta): retire legacy SQLite ticket/decision tooling (pql migration phase 6)

The pql cutover is stable, so remove the superseded SQLite planning tooling. Surgical
— only the ticket/decision/raw-SQL scripts (all settledreach.db-bound and replaced by
pql) are deleted; the asset/audio/wiki connectors and shared common.py stay.

Removed:
- tooling/db/{ticket,decision,decisions-sync,decisions_sync.py,sqlite-query,sqlite-exec,
  sqlite-init,sqlite-seed,sqlite_connector.py}
- tooling/{db-backup,db-install} + docs/backups/settledreach.db.backup (the binary-DB
  backup ritual; tickets now live in the git-tracked .pql/changelog/)
- tooling/check-decision-ids (dead stub, superseded by `pql decisions validate`)
- Makefile db-backup/db-install targets; SR_DB_PATH + tooling/db/{ticket,sqlite-*,
  decision*} entries from .claude/settings.json (audio entries kept)

Updated docs to pql: DEVOPS.md (SQLite Access + Decisions System → pql), project
structure, ticket-cli closing note, asset-pipeline raw-SQL warning.

Kept (verified still imported by the asset connectors via common.ensure_venv): common.py,
config.json, audio/image/trellis/wiki connectors. The live settledreach.db file
(gitignored, repo-parent) is left on disk as a cold rollback only.

ruff clean; pql decisions validate ok (357 decisions / 1013 tickets).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.claude/rules/asset-pipeline.md

@@ -160,7 +160,7 @@ the stamp picks it up automatically.
 
 **NOT legitimate and forbidden:**
 
-- Running `tooling/db/sqlite-exec` (or any raw SQL) against `systems.db` by
+- Running any raw SQL (e.g. the `sqlite3` CLI) against `systems.db` by
   hand.  Any changes you make are silently reverted by the next `regen-db` run
   — your edits die, not the pipeline's.
 - One-off patch scripts that open `systems.db` and modify rows.