fix(mcp): add sanctioned gitea_edit_issue and a doc/registry drift guard (Closes #781)

The gitea-workflow documentation named a gitea_edit_issue tool that no
namespace had ever registered. There was no sanctioned MCP path to change an
issue title or body at all: the only edit tool, gitea_edit_pr, PATCHes the
pull-request endpoint. An authorized body correction on issue #780 therefore
had to be recorded as a discussion comment instead.

Add edit_issue.py as the authoritative rule and gitea_edit_issue as the tool
built on it:

- Only the fields the caller names are sent, so labels, state, assignee, and
  milestone cannot be overwritten from a stale read.
- A pull-request number is refused. Gitea serves pull requests from the same
  /issues/{n} collection, so without that check the issue path would quietly
  become a second, ungated PR edit path. gitea_edit_pr stays PR-only.
- Structurally invalid requests raise before any credential or network work;
  a request that would change nothing is reported as an explicit no-op with a
  next action rather than a silent success.
- Read-after-write proves the applied title/body and proves that state,
  labels, assignees, and milestone did not move. Transport failures on the
  pre-read, the PATCH, and the read-back are each reported, redacted, with
  the correct performed/verified state.

Gates match every other issue mutation: profile permission via the shared
capability map (resolver task edit_issue, gitea.issue.comment), preflight
purity, branches worktree validation, anti-stomp inventory membership, and
audited mutation.

Fix the drift that hid this. docs/mcp-tool-inventory.md is now the canonical
registered-tool list, and mcp_tool_inventory.py compares it to the live
registry in both directions, plus checks that every tool named under skills/
is registered. The new guard immediately found a second instance of the same
defect: gitea_record_pre_review_command had lost its @mcp.tool() decorator
while the canonical review workflow still instructed reviewers to call it, so
that registration is restored.

Validation:
PASSED: venv/bin/python -m pytest tests/test_issue_781_edit_issue_tool.py -s -q
  — 50 passed
FAILED: venv/bin/python -m pytest -s -q — 4095 passed, 11 failed, 6 skipped.
  The identical 11 tests fail on clean master 8e149e6 with no changes applied
  (254 passed, 11 failed across those five files), so they are pre-existing
  and proven by a baseline run rather than asserted.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

docs/mcp-tool-inventory.md

@@ -0,0 +1,169 @@
+# Registered MCP tool inventory
+
+This is the canonical list of tools the Gitea-Tools MCP server registers. It
+exists because documentation and the registered inventory drifted: the workflow
+documented a `gitea_edit_issue` tool that no namespace had ever registered, so a
+mutation could be planned against a tool that did not exist and only fail at
+execution time (#781).
+
+## The rule
+
+**Documentation must never name a tool an actor cannot reach.**
+
+Two guards enforce it, both in `tests/test_issue_781_edit_issue_tool.py`:
+
+1. The list below must equal the registered tool set exactly — sorted, no
+   duplicates, nothing missing in either direction. Adding a tool without
+   documenting it fails, and documenting a tool without registering it fails.
+2. Every backticked `gitea_*` / `mcp_*` identifier in `skills/**/*.md` must be a
+   registered tool. Module and script names that share the prefix are listed
+   explicitly in `mcp_tool_inventory.NON_TOOL_IDENTIFIERS` rather than being
+   waved through by a looser pattern.
+
+## Updating this file
+
+When you add or remove an `@mcp.tool()`, regenerate the block below:
+
+```bash
+PYTEST_CURRENT_TEST=1 venv/bin/python -c "
+import mcp_server, mcp_tool_inventory
+print(mcp_tool_inventory.render_inventory_block(
+    mcp_server.mcp._tool_manager._tools))
+"
+```
+
+Replace everything between the markers with that output. Do not hand-edit
+individual entries — the generator and the guard share one ordering rule.
+
+## Registered tools
+
+Namespaces (`gitea-tools`, `gitea-reviewer`, `gitea-merger`, `gitea-reconciler`)
+register the same tool set; what differs per namespace is the execution profile
+that gates each call, not which tools exist.
+
+<!-- BEGIN REGISTERED TOOL INVENTORY -->
+
+- `gitea_abandon_workflow_lease`
+- `gitea_acquire_conflict_fix_lease`
+- `gitea_acquire_merger_pr_lease`
+- `gitea_acquire_reviewer_pr_lease`
+- `gitea_activate_profile`
+- `gitea_adopt_merger_pr_lease`
+- `gitea_adopt_workflow_lease`
+- `gitea_allocate_next_work`
+- `gitea_assess_already_landed_reconciliation`
+- `gitea_assess_conflict_fix_classification`
+- `gitea_assess_conflict_fix_push`
+- `gitea_assess_gitea_operation_path`
+- `gitea_assess_master_parity`
+- `gitea_assess_mcp_namespace_health`
+- `gitea_assess_pr_sync_status`
+- `gitea_assess_review_merge_state_machine`
+- `gitea_assess_reviewer_pr_lease`
+- `gitea_assess_terminal_label_hygiene`
+- `gitea_assess_work_issue_duplicate`
+- `gitea_assess_worktree_cleanup_integrity`
+- `gitea_audit_config`
+- `gitea_audit_stable_branch_contamination`
+- `gitea_audit_worktree_cleanup`
+- `gitea_authorize_reconciliation_cleanup_phase`
+- `gitea_authorize_review_correction`
+- `gitea_capability_stop_terminal_report`
+- `gitea_capture_branches_worktree_snapshot`
+- `gitea_check_pr_eligibility`
+- `gitea_cleanup_merged_pr_branch`
+- `gitea_cleanup_obsolete_reviewer_comment_lease`
+- `gitea_cleanup_post_merge_moot_lease`
+- `gitea_cleanup_stale_claims`
+- `gitea_cleanup_stale_review_decision_lock`
+- `gitea_cleanup_terminal_pr_labels`
+- `gitea_close_issue`
+- `gitea_commit_files`
+- `gitea_consume_irrecoverable_decision_lock_provenance`
+- `gitea_create_issue`
+- `gitea_create_issue_comment`
+- `gitea_create_label`
+- `gitea_create_pr`
+- `gitea_delete_branch`
+- `gitea_diagnose_review_decision_lock`
+- `gitea_diagnose_reviewer_pr_lease_handoff`
+- `gitea_diagnose_terminal`
+- `gitea_dry_run_pr_review`
+- `gitea_edit_issue`
+- `gitea_edit_pr`
+- `gitea_expire_workflow_leases`
+- `gitea_get_authenticated_user`
+- `gitea_get_current_user`
+- `gitea_get_file`
+- `gitea_get_pr_review_feedback`
+- `gitea_get_profile`
+- `gitea_get_runtime_context`
+- `gitea_get_shell_health`
+- `gitea_heartbeat_reviewer_pr_lease`
+- `gitea_inspect_workflow_lease`
+- `gitea_issue_irrecoverable_provenance_authorization`
+- `gitea_list_issue_comments`
+- `gitea_list_issues`
+- `gitea_list_labels`
+- `gitea_list_profiles`
+- `gitea_list_prs`
+- `gitea_list_workflow_leases`
+- `gitea_load_review_workflow`
+- `gitea_lock_issue`
+- `gitea_mark_final_review_decision`
+- `gitea_mark_issue`
+- `gitea_merge_pr`
+- `gitea_mirror_refs`
+- `gitea_observability_link_issue`
+- `gitea_observability_list_projects`
+- `gitea_observability_reconcile_incident`
+- `gitea_post_heartbeat`
+- `gitea_quarantine_contaminated_review`
+- `gitea_reclaim_expired_workflow_lease`
+- `gitea_reconcile_already_landed_pr`
+- `gitea_reconcile_issue_claims`
+- `gitea_reconcile_merged_cleanups`
+- `gitea_reconcile_superseded_by_merged_pr`
+- `gitea_record_irrecoverable_decision_lock_provenance`
+- `gitea_record_pre_review_command`
+- `gitea_record_shell_spawn_outcome`
+- `gitea_record_stable_branch_push_attempt`
+- `gitea_release_merger_pr_lease`
+- `gitea_release_reviewer_pr_lease`
+- `gitea_release_workflow_lease`
+- `gitea_resolve_task_capability`
+- `gitea_resume_review_draft`
+- `gitea_review_pr`
+- `gitea_route_task_session`
+- `gitea_save_review_draft`
+- `gitea_scan_already_landed_open_prs`
+- `gitea_sentry_get_issue_events`
+- `gitea_sentry_link_gitea_issue`
+- `gitea_sentry_list_issues`
+- `gitea_sentry_reconcile_issue`
+- `gitea_sentry_watchdog`
+- `gitea_set_issue_labels`
+- `gitea_submit_pr_review`
+- `gitea_update_pr_branch_by_merge`
+- `gitea_validate_review_final_report`
+- `gitea_view_issue`
+- `gitea_view_pr`
+- `gitea_whoami`
+- `gitea_workflow_dashboard`
+- `mcp_check_workflow_skill_preflight`
+- `mcp_get_control_plane_guide`
+- `mcp_get_skill_guide`
+- `mcp_list_project_skills`
+
+<!-- END REGISTERED TOOL INVENTORY -->
+
+## Issue-content editing
+
+`gitea_edit_issue` is the only path that changes an issue's title or body. It
+PATCHes the issue endpoint, refuses a pull-request number, sends only the fields
+the caller named, and proves the result by read-after-write — including that
+state, labels, assignees, and milestone did not move.
+
+`gitea_edit_pr` remains pull-request-only. The two paths never merge: a single
+tool that accepted either kind would make the narrower capability reachable
+through the wider one.