feat(deacon): add github-gate-check step to patrol formula

Adds the missing github-gate-check step that runs `bd gate discover` and
`bd gate check --type=gh` to evaluate GitHub CI gates. Updates
dispatch-gated-molecules to depend on both gate-evaluation and
github-gate-check.

Fixes: gt-sfxpr

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/formula/formulas/mol-deacon-patrol.formula.toml

@@ -23,7 +23,7 @@ Witnesses detect it and escalate to the Mayor.
 The Deacon's agent bead last_activity timestamp is updated during each patrol
 cycle. Witnesses check this timestamp to verify health."""
 formula = "mol-deacon-patrol"
-version = 6
+version = 7
 
 [[steps]]
 id = "inbox-check"
@@ -148,10 +148,52 @@ bd gate list --json
 After closing a gate, the Waiters field contains mail addresses to notify.
 Send a brief notification to each waiter that the gate has cleared."""
 
+[[steps]]
+id = "github-gate-check"
+title = "Check GitHub CI gates"
+needs = ["inbox-check"]
+description = """
+Discover and evaluate GitHub CI gates.
+
+GitHub gates (await_type: gh:run, gh:pr) require checking external CI status.
+This step discovers new gates from GitHub activity and evaluates pending ones.
+
+**Step 1: Discover new GitHub gates**
+```bash
+bd gate discover
+```
+
+This scans for GitHub CI gates that should be created based on:
+- Active PRs with required CI checks
+- Workflow runs that molecules are waiting on
+
+**Step 2: Evaluate pending GitHub gates**
+```bash
+bd gate check --type=gh
+```
+
+For each GitHub gate, this checks:
+- gh:run gates: Has the workflow run completed? Did it succeed?
+- gh:pr gates: Has the PR been merged/closed?
+
+Gates that pass their condition are automatically closed.
+
+**Step 3: Report closures**
+For any gates that were just closed, log the result:
+```bash
+# Gate <id> closed: GitHub CI passed
+# Gate <id> closed: PR merged
+```
+
+**If no GitHub gates exist:**
+Skip - nothing to check.
+
+**Exit criteria:** All GitHub gates evaluated, passing gates closed."""
+
 [[steps]]
 id = "dispatch-gated-molecules"
 title = "Dispatch molecules with resolved gates"
-needs = ["gate-evaluation"]
+needs = ["gate-evaluation", "github-gate-check"]
 description = """
 Find molecules blocked on gates that have now closed and dispatch them.