fix(mcp): block manual daemon killing as workflow recovery (Closes #630)

A session that ran `pkill -f mcp_server.py`, waited for the IDE to respawn
the daemons, and then closed an issue left no trace distinguishing that
closure from one performed over a sanctioned runtime. Detection existed only
as advisory strings (`native_mcp_preference.classify_command_path`,
`review_workflow_boundary`) and never failed closed on the mutations that
followed.

Adds `runtime_recovery_guard.py`, mirroring the #671 stable-branch
contamination model so the two cannot drift apart: classification of
kill/pkill/killall commands and known-pid kills, a durable
`runtime_recovery_contamination` marker, a fail-closed pre-flight gate over
the shared review/merge/close/completion task set, and reconciler-only
clearing. `comment_issue` and `lock_issue` stay allowed so a contaminated
worker can still post its audit comment and hand off. The marker is
recovery-critical, so contamination cannot expire into cleanliness with the
session-state TTL.

Read-only inspection (`ps aux | grep mcp_server`), sanctioned reconnects,
and process management unrelated to the daemons are never flagged; a bare
`kill` of an unknown pid is reported as ambiguous rather than contaminating,
so ordinary subprocess work is not false-blocked. A pattern broad enough to
sweep unrelated namespaces (`pkill -f python`) is contamination even when it
never names MCP.

Operator-authorized host maintenance stays permitted, but the authorization
is read from GITEA_OPERATOR_DAEMON_MAINTENANCE_AUTHORIZATION in the process
environment only and never from a tool argument, so a session cannot
authorize itself.

Final-report rules reject clean-session claims and require the contaminated
recovery to be surfaced. Two tools are registered (inventory 112 to 114) and
the sanctioned-versus-forbidden contrast is documented in the namespace
recovery doc and the workflow skill.

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

docs/mcp-tool-inventory.md

@@ -64,6 +64,7 @@ that gates each call, not which tools exist.
 - `gitea_assess_work_issue_duplicate`
 - `gitea_assess_worktree_cleanup_integrity`
 - `gitea_audit_config`
+- `gitea_audit_runtime_recovery_contamination`
 - `gitea_audit_stable_branch_contamination`
 - `gitea_audit_worktree_cleanup`
 - `gitea_authorize_reconciliation_cleanup_phase`
@@ -125,6 +126,7 @@ that gates each call, not which tools exist.
 - `gitea_reconcile_issue_claims`
 - `gitea_reconcile_merged_cleanups`
 - `gitea_reconcile_superseded_by_merged_pr`
+- `gitea_record_daemon_process_kill_attempt`
 - `gitea_record_irrecoverable_decision_lock_provenance`
 - `gitea_record_pre_review_command`
 - `gitea_record_shell_spawn_outcome`