fix: bug: architect pitch prompt guardrail is prose-only — model bypasses "NEVER call Forgejo API" via Bash tool; fix via permission scoping + PR-driven sub-issue filing (#764)

Shift the guardrail from prose prompt constraints into Forgejo's permission
layer. architect-bot loses all write access on the project repo (now read-only
for context gathering). Sub-issues are produced by a new filer-bot identity
that runs only after a human merges a sprint PR on the ops repo.

Changes:
- architect-run.sh: remove all project-repo writes (add_inprogress_label,
  close_vision_issue, check_and_close_completed_visions); add ## Sub-issues
  block to pitch format with filer:begin/end markers
- formulas/run-architect.toml: add Sub-issues schema to pitch format; strip
  issue-creation API refs; document read-only constraint on project repo
- lib/formula-session.sh: remove Create issue curl template from
  build_prompt_footer (architect cannot create issues)
- lib/sprint-filer.sh (new): parser + idempotent filer using FORGE_FILER_TOKEN;
  parses filer:begin/end blocks, creates issues with decomposed-from markers,
  adds in-progress label, handles vision lifecycle closure
- .woodpecker/ops-filer.yml (new): CI pipeline on ops repo main-branch push
  that invokes sprint-filer.sh after sprint PR merge
- lib/env.sh, .env.example, docker-compose.yml: add FORGE_FILER_TOKEN for
  filer-bot identity; add filer-bot to FORGE_BOT_USERNAMES
- AGENTS.md: add Filer agent entry; update in-progress label docs
- .woodpecker/agent-smoke.sh: register sprint-filer.sh for smoke test

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.env.example

@@ -45,7 +45,9 @@ FORGE_PREDICTOR_TOKEN=                     # [SECRET] predictor-bot API token
 FORGE_PREDICTOR_PASS=                      # [SECRET] predictor-bot password for git HTTP push
 FORGE_ARCHITECT_TOKEN=                     # [SECRET] architect-bot API token
 FORGE_ARCHITECT_PASS=                      # [SECRET] architect-bot password for git HTTP push
-FORGE_BOT_USERNAMES=dev-bot,review-bot,planner-bot,gardener-bot,vault-bot,supervisor-bot,predictor-bot,architect-bot
+FORGE_FILER_TOKEN=                         # [SECRET] filer-bot API token (issues:write on project repo only)
+FORGE_FILER_PASS=                          # [SECRET] filer-bot password for git HTTP push
+FORGE_BOT_USERNAMES=dev-bot,review-bot,planner-bot,gardener-bot,vault-bot,supervisor-bot,predictor-bot,architect-bot,filer-bot
 
 # ── Backwards compatibility ───────────────────────────────────────────────
 # If CODEBERG_TOKEN is set but FORGE_TOKEN is not, env.sh falls back to