feat(conventions): generalize defaults, backfill old projects, adopt the standard in-repo

Harden the architectural-conventions standard so it works out-of-the-box on
any project and resolves for projects that predate it, and make RoboCo pass
its own gate.

General defaults (apply to every project, not just one with a tuned file):
- The auto-scan excludes test and documentation trees (tests/, docs/) — those
  legitimately define fixtures and aren't enforced code.
- Helper placement seeds at warn, not block: `helper` matches any top-level
  function, too blunt a signal to hard-block a route file's small private glue.
  Misplaced model/route/component stay block; the body-level thin_routes check
  remains the real fat-handler guard.
- thin_routes no longer counts transaction-lifecycle calls (commit/flush/
  refresh) as data access — an explicit `db.commit()` after delegating to a
  service is a valid pattern.
- no_lint_suppressions exempts a small allowlist of structurally-unavoidable
  framework codes (ruff TC001-TC003, pydantic prop-decorator); bare or other
  suppressions still flag.
- CLAUDE.md rule-lifting skips bare common-word tokens that would match
  everywhere (e.g. "commit"), keeping only specific identifiers.
- The ambient prompt block lists only constrained modules and truncates at a
  line boundary with a "+N more" pointer instead of cutting mid-line.

Backfill: the standard previously read the committed file + repo scan from
project.workspace_path, a field only a manual API call set — so an older
project (or one whose workspace was cleared) showed an empty "missing" map no
matter what was pushed. The service now ensures a dedicated, default-branch
read clone on demand (WorkspaceService.ensure_read_clone) and resolves from
it, persisting the resolved path + real HEAD. The panel tab, the spawn-time
ambient block, and the per-task constraints all resolve the committed standard
with no manual setup.

Adopt in-repo: relocate the inline request/response models from the system and
*_live route modules into roboco/api/schemas/ so the codebase passes its own
placement gate, and ship a canonical .roboco/conventions.yml. no_models_in_routes
and modular_cohesion are now clean and enforced at block.

Docs updated across the user guide, the agent-facing RAG standard, the
developer and pr_reviewer role prompts, CLAUDE.md, and the changelog. New unit
tests cover the scan exclusions, helper-warn, the suppression allowlist, the
commit exemption, and the resolve/backfill path; the conventions + project
integration suites pass against Postgres.

tests/unit/conventions/test_scan.py

@@ -48,11 +48,35 @@ def test_scan_ignores_vendored_directories(tmp_path: Path) -> None:
 
 def test_scan_lifts_claude_md_imperative_into_custom_rule(tmp_path: Path) -> None:
     _sample_repo(tmp_path)
-    (tmp_path / "CLAUDE.md").write_text("- Never use `print()`; use the logger.\n")
+    (tmp_path / "CLAUDE.md").write_text("- Never call `os.system()`; use subprocess.\n")
     custom = derive_from_scan(tmp_path).custom
     assert custom
     assert custom[0].level == "warn"
-    assert "print" in custom[0].pattern
+    assert custom[0].id == "os-system"
+
+
+def test_scan_skips_bare_common_word_in_claude_md(tmp_path: Path) -> None:
+    # A bare word like `commit` would match everywhere; it must not be lifted.
+    _sample_repo(tmp_path)
+    (tmp_path / "CLAUDE.md").write_text("- Never `commit` straight to master.\n")
+    assert derive_from_scan(tmp_path).custom == []
+
+
+def test_scan_excludes_test_and_docs_trees(tmp_path: Path) -> None:
+    (tmp_path / "tests" / "unit" / "services").mkdir(parents=True)
+    (tmp_path / "docs" / "api").mkdir(parents=True)
+    (tmp_path / "app" / "services").mkdir(parents=True)
+    paths = {m.path for m in derive_from_scan(tmp_path).modules}
+    assert "app/services" in paths
+    assert not any(p.startswith(("tests/", "docs/")) for p in paths)
+
+
+def test_scan_seeds_helper_placement_as_warn(tmp_path: Path) -> None:
+    _sample_repo(tmp_path)
+    std = derive_from_scan(tmp_path)
+    # A misplaced model is a hard error; a misplaced helper only warns.
+    assert std.rules["no_models_in_routers"].level == "block"
+    assert std.rules["no_helpers_in_routers"].level == "warn"
 
 
 def test_render_yaml_round_trips_through_parse(tmp_path: Path) -> None: