feat: make master-parity live-remote aware so a stale daemon fails closed (Closes #610)

Master-parity previously compared only the daemon's startup commit against the
local on-disk HEAD. When the checkout was not pulled, parity reported green even
though the live remote master had advanced, so a stale daemon could claim a
mutation-safe result while running outdated capability gates (observed during
PR #592 recovery, where the resolver correctly required restart but parity said
in_parity=true).

Changes:
- master_parity_gate.assess_master_parity() gains an optional live_remote_head
  and reports the three commits distinctly (daemon_start_head, local_head,
  live_remote_head) plus live_known / live_stale / mutation_safe. A result is
  mutation_safe only when daemon, local checkout, and live remote all agree.
- parity_block_reasons() now blocks mutations on live-staleness too; read-only
  operations remain unblocked (non-goal: never block diagnostics offline).
- New parity_resolver_disagreement(): typed fail-closed blocker naming the
  capability resolver as authoritative when it requires restart but parity
  looks locally green.
- New read_remote_master_head(): best-effort `git ls-remote` for the live
  target, cached with a 60s TTL (bounded offline latency, no network probe per
  gate call); env override GITEA_TEST_LIVE_REMOTE_HEAD keeps tests hermetic.
- Server: _current_master_parity() reads the live remote head;
  gitea_assess_master_parity and runtime_context surface the distinguished
  SHAs, mutation_safe, and resolver-authoritative guidance.

Tests: 13 new cases (live-remote parity, live-stale blocking + typed blocker,
remote-head reader + TTL cache, server wiring). Full suite: 2423 passed; the 8
remaining failures (test_config TestAuthIntegration, test_credentials
TestGetCredentials) are baseline-proven keychain/env failures identical on the
unmodified base.

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

gitea_mcp_server.py

@@ -6609,10 +6609,39 @@ def _try_auto_switch_for_operation(op: str, host: str | None = None) -> bool:
     return False
 
 
+def _git_default_remote_name(root: str) -> str:
+    """First configured git remote name for *root*, defaulting to 'origin'.
+
+    Used to resolve the live remote master target for parity (#610). Best
+    effort: any failure falls back to 'origin' so callers never raise.
+    """
+    try:
+        res = subprocess.run(
+            ["git", "-C", root, "remote"],
+            capture_output=True, text=True, check=False,
+        )
+    except Exception:
+        return "origin"
+    if res.returncode != 0:
+        return "origin"
+    names = [n.strip() for n in (res.stdout or "").splitlines() if n.strip()]
+    return names[0] if names else "origin"
+
+
 def _current_master_parity() -> dict:
-    """Assess this process's code against the on-disk master HEAD (#420)."""
+    """Assess this process's code against local and live remote master (#420/#610).
+
+    Compares the daemon's startup commit, the on-disk checkout HEAD, and the
+    live remote master target. A stale daemon relative to live master fails
+    closed for mutations even when the local checkout HEAD still matches the
+    startup commit. The live-remote read is best effort: an unresolved live
+    head leaves read-only diagnostics unblocked but is never mutation-safe.
+    """
     current_head = master_parity_gate.read_git_head(PROJECT_ROOT)
-    return master_parity_gate.assess_master_parity(_STARTUP_PARITY, current_head)
+    live_head = master_parity_gate.read_remote_master_head(
+        PROJECT_ROOT, remote=_git_default_remote_name(PROJECT_ROOT))
+    return master_parity_gate.assess_master_parity(
+        _STARTUP_PARITY, current_head, live_remote_head=live_head)
 
 
 def _master_parity_block(op: str) -> list[str]:
@@ -8942,15 +8971,34 @@ def gitea_get_runtime_context(
         "restart_required": parity["restart_required"],
         "startup_head": parity["startup_head"],
         "current_head": parity["current_head"],
+        # #610 distinguished mutation-safety signals:
+        "daemon_start_head": parity["daemon_start_head"],
+        "local_head": parity["local_head"],
+        "live_remote_head": parity["live_remote_head"],
+        "live_known": parity["live_known"],
+        "live_stale": parity["live_stale"],
+        "mutation_safe": parity["mutation_safe"],
         "summary": master_parity_gate.format_parity(parity),
         "mutation_gate_enforced": not master_parity_gate.gate_disabled(),
+        # #610: the capability resolver is authoritative for mutation safety;
+        # local parity alone must never authorize a mutation.
+        "resolver_authoritative_for_mutation_safety": True,
     }
-    if parity["stale"] and not master_parity_gate.gate_disabled():
-        safe_next_action = (
-            "Server code is stale relative to master; restart the Gitea MCP "
-            "server to load current capability gates before mutating. "
-            f"({master_parity_gate.format_parity(parity)})"
-        )
+    if parity["restart_required"] and not master_parity_gate.gate_disabled():
+        if parity["live_stale"]:
+            safe_next_action = (
+                "Daemon is stale relative to LIVE remote master "
+                f"(started {parity['startup_head'][:12] if parity['startup_head'] else 'unknown'}, "
+                f"live master {parity['live_remote_head'][:12] if parity['live_remote_head'] else 'unknown'}); "
+                "restart/reconnect the Gitea MCP server before mutating. The "
+                "capability resolver is authoritative for mutation safety."
+            )
+        else:
+            safe_next_action = (
+                "Server code is stale relative to master; restart the Gitea MCP "
+                "server to load current capability gates before mutating. "
+                f"({master_parity_gate.format_parity(parity)})"
+            )
         result["safe_next_action"] = safe_next_action
 
     if reveal and h:
@@ -8989,12 +9037,19 @@ def gitea_assess_master_parity(
         "determinable": parity["determinable"],
         "startup_head": parity["startup_head"],
         "current_head": parity["current_head"],
+        # #610 distinguished mutation-safety signals:
+        "daemon_start_head": parity["daemon_start_head"],
+        "local_head": parity["local_head"],
+        "live_remote_head": parity["live_remote_head"],
+        "live_known": parity["live_known"],
+        "live_stale": parity["live_stale"],
+        "mutation_safe": parity["mutation_safe"],
         "mutation_gate_enforced": enforced,
         "summary": master_parity_gate.format_parity(parity),
         "reasons": parity["reasons"],
         "process_root": PROJECT_ROOT,
     }
-    if parity["stale"] and enforced:
+    if parity["restart_required"] and enforced:
         out["report"] = master_parity_gate.parity_report(parity)
     return out
 def gitea_record_pre_review_command(