add Python stopgap planning tooling under tools/scripts/plan

Ports settled-reach's decisions_sync.py + ticket + decision scripts,
Scrum-stripped. Writes to .pql/pql.db (gitignored). Verb shape
mirrors the eventual `pql` subcommands so migration is a call-site
find-replace once pql ships feature parity (D-040, R-011).

Ticket IDs are T-NNN (TEXT PKs) — reshape from settled-reach's
integer auto-increment so the stopgap's writes are compatible with
pql's future reads without a data migration. No `sprints` table; the
pyramid is kanban / waterfall (D-035).

Verified end-to-end: sync parses 71 records (39 confirmed, 23 open
questions, 9 rejected) with 62 cross-refs and zero broken links;
`ticket new`, `ticket status`, `ticket board`, and `decisions show
--with-refs` all round-trip correctly.

Co-Authored-By: Claude <noreply@anthropic.com>

tools/scripts/README.md

@@ -0,0 +1,49 @@
+# STOPGAP — Planning tooling
+
+This directory is a **time-limited stopgap**. The Python scripts here
+port settled-reach's `decisions_sync.py` + `ticket` + `decision`
+scripts, Scrum-stripped, and write to `.pql/pql.db` (gitignored).
+
+## Sunset clause
+
+Per [`D-040`](../../decisions/process.md#d-040-python-stopgap-under-toolsscriptsplan)
+and [`R-011`](../../decisions/rejected.md#r-011-permanent-stopgap),
+this stopgap deletes when pql ships:
+
+- `pql decisions sync | validate | list | show | claim | coverage`
+- `pql ticket new | list | show | status | assign | block | board`
+
+with feature parity on the same `.pql/pql.db` file this stopgap wrote.
+
+Migration is a call-site find-replace:
+
+```
+tools/scripts/plan decisions sync        →  pql decisions sync
+tools/scripts/plan ticket new task "…"   →  pql ticket new task "…"
+tools/scripts/plan ticket board          →  pql ticket board
+```
+
+See [`Q-021`](../../decisions/questions-architecture.md#q-021-pql-absorbs-planning-vs-keeps-separate)
+for the open gate on whether pql absorbs planning long-term.
+
+## Entrypoint
+
+`plan` is a Python executable. Support modules live under `planning/`.
+
+```
+plan decisions sync | validate | claim D|Q|R <domain> [title] | list | show <id> | coverage
+plan ticket    new <type> "title" | list | show <id> | status <id> <new> | assign <id> <agent>
+plan ticket    block <id> --by <other> | unblock <id> --from <other>
+plan ticket    team <id> <team> | label <id> add|rm <label> | board | search "query"
+plan sqlite-query "SELECT …"
+```
+
+Needs Python 3.9+ (f-strings + `pathlib`). No third-party deps.
+
+## Where things live
+
+- DB: `.pql/pql.db` (gitignored, per-dev)
+- Records (source of truth): `decisions/*.md`
+- Tickets: today SQLite-only; see
+  [`Q-022`](../../decisions/questions-architecture.md#q-022-ticket-persistence-strategy)
+  for the markdown-mirror question.