feat(intent): /trekplan halts without an approved intent; the approval is stamped on both paths

Veikart steg 1, økt 1 av 2. The three holes measured in the grounds:
(1) ## Intent / ## Goal were only checked for existence, (2) no approval
marker existed, (3) brief-approved was emitted only on the auto path.

- lib/validators/intent-approval.mjs: --check / --stamp. The marker is
  intent_approved_hash (sha256 over normalized ## Intent + ## Goal) +
  intent_approved_at. Editing either section after approval → STALE.
- /trekplan Phase 1 (Read the brief, both --brief and --project): runs
  --check and HALTS on BRIEF_INTENT_NOT_APPROVED / _STALE / _INVALID with
  the remedy spelled out; an unrunnable check halts too.
- /trekbrief Phase 4h (before the Phase 5 fork, asked even in --quick):
  shows Intent + Goal verbatim, AskUserQuestion Approve / Revise / Leave;
  only "Approve" runs --stamp. --stamp emits brief-approved, so the manual
  (default) path records it; the auto path's own emission is removed.
  New mode /trekbrief --approve <project-dir> = Phase 4h alone.
- README, CLAUDE.md, command-modes, HANDOVER-CONTRACTS §Handover 1,
  jsonl-schemas (trekbrief-stats gains intent_approved).

Valgt ingen brief_version-bump fordi skjemaendringen er rent additiv (to
valgfrie felt) og kravet sitter i /trekplan — enhver produsents brief kan
godkjennes via /trekbrief --approve uten produsentendring. Valgt eget
--check-kall i stedet for et flagg på brief-validator fordi --brief-stien
i dag ikke kjører validatoren i det hele tatt; et nytt validatorkall der
ville også stoppe på andre feil. Valgt fallback-datamappe = målestokkens
(plugins/data/voyage-…) fordi CLAUDE_PLUGIN_DATA er tom i Bash-miljøet og
event-emits egen fallback er stille skip — slik ble brief-approved 0 records.

What the marker does NOT prove (module header, command prose, contract):
same user, same machine — any session can stamp. A trace, not a signature.

Suite 1183 → 1201 (1199/0/2). Mutants M1–M5 (stale check off, check
always valid, gate line removed, stamp emits nothing, no normalization)
each fell ≥ 1 test. yardstick unchanged: RED, 1 of 3 countable.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/command-modes.md

@@ -10,6 +10,7 @@ Per-command flag tables, imported from `CLAUDE.md` via pointer.
 | `--quick` | Compact start; still escalates if required sections are weak or the brief-review gate fails → brief.md with research plan |
 | `--gates {true\|false}` | (v3.4.0) Boolean autonomy-gate flag; present → gating on. Policy (`gates_mode`) detailed under `## Autonomy mode` in `docs/operations.md`. |
 | `--profile <name>` | (v4.1.0) Model profile: `economy` / `balanced` / `premium` / `fable` / `<custom>`. Sets `phase_models` for the brief phase. See `## Profile system` in `docs/operations.md`. |
+| `--approve <project-dir>` | (veikart steg 1) No interview: show the existing brief's `## Intent` + `## Goal` verbatim, ask the operator to approve, and on "Approve" stamp `intent_approved_hash` + `intent_approved_at` and emit `brief-approved`. The remedy `/trekplan` names when it halts on `BRIEF_INTENT_NOT_APPROVED` / `BRIEF_INTENT_APPROVAL_STALE`. |
 
 Always interactive. Phase 3 is a section-driven completeness loop (no hard cap on question count); Phase 4 runs a `brief-reviewer` stop-gate with max 3 review iterations. After writing the brief, asks the user to choose manual (print commands) or auto (Claude runs research + plan in foreground).