fix: update AGENTS.md docs and handle stale PHASE:escalate in gardener

Address review feedback:
- gardener/AGENTS.md: remove escalation flow references, describe vault routing
- supervisor/AGENTS.md: remove escalation flow references, describe vault routing
- gardener-run.sh: treat PHASE:escalate as terminal (kills session) to prevent
  zombie sessions from stale/legacy escalation writes

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

gardener/AGENTS.md

@@ -1,29 +1,27 @@
-<!-- last-reviewed: 043bf0f0217aef3f319b844f1a1277acd6327a1c -->
+<!-- last-reviewed: f2064ba67c3b6819f5e252300927c01e2825dd7c -->
 # Gardener Agent
 
 **Role**: Backlog grooming — detect duplicate issues, missing acceptance
 criteria, oversized issues, stale issues, and circular dependencies. Enforces
 the quality gate: strips the `backlog` label from issues that lack acceptance
 criteria checkboxes (`- [ ]`) or an `## Affected files` section. Invokes
-Claude to fix or escalate to a human via Matrix.
+Claude to fix what it can; files vault items for what it cannot.
 
 **Trigger**: `gardener-run.sh` runs 4x/day via cron. Sources `lib/guard.sh` and
 calls `check_active gardener` first — skips if `$FACTORY_ROOT/state/.gardener-active`
 is absent. Then creates a tmux session with `claude --model sonnet`, injects
-`formulas/run-gardener.toml` with escalation replies as context, monitors the
-phase file, and cleans up on completion or timeout (2h max session). No action
-issues — the gardener runs directly from cron like the planner, predictor, and
-supervisor.
+`formulas/run-gardener.toml` as context, monitors the phase file, and cleans up
+on completion or timeout (2h max session). No action issues — the gardener runs
+directly from cron like the planner, predictor, and supervisor.
 
 **Key files**:
 - `gardener/gardener-run.sh` — Cron wrapper + orchestrator: lock, memory guard,
-  consumes escalation replies, sources disinto project config, creates tmux session,
-  injects formula prompt, monitors phase file via custom `_gardener_on_phase_change`
-  callback (passed to `run_formula_and_monitor`). Kills session on `PHASE:escalate`
-  to prevent zombies. Stays alive through CI/review/merge cycle after `PHASE:awaiting_ci`
-  — injects CI results and review feedback, re-signals `PHASE:awaiting_ci` after
-  fixes, signals `PHASE:awaiting_review` on CI pass. Executes pending-actions
-  manifest after PR merge.
+  sources disinto project config, creates tmux session, injects formula prompt,
+  monitors phase file via custom `_gardener_on_phase_change` callback (passed to
+  `run_formula_and_monitor`). Stays alive through CI/review/merge cycle after
+  `PHASE:awaiting_ci` — injects CI results and review feedback, re-signals
+  `PHASE:awaiting_ci` after fixes, signals `PHASE:awaiting_review` on CI pass.
+  Executes pending-actions manifest after PR merge.
 - `formulas/run-gardener.toml` — Execution spec: preflight, grooming, dust-bundling, blocked-review, agents-update, commit-and-pr
 - `gardener/pending-actions.json` — Manifest of deferred repo actions (label changes,
   closures, comments, issue creation). Written during grooming steps, committed to the
@@ -35,10 +33,10 @@ supervisor.
 - `MATRIX_TOKEN`, `MATRIX_ROOM_ID`, `MATRIX_HOMESERVER`
 
 **Lifecycle**: gardener-run.sh (cron 0,6,12,18) → `check_active gardener` → lock + memory guard →
-consume escalation replies → load formula + context → create tmux session →
+load formula + context → create tmux session →
 Claude grooms backlog (writes proposed actions to manifest), bundles dust,
 reviews blocked issues, updates AGENTS.md, commits manifest + docs to PR →
 `PHASE:awaiting_ci` (stays alive) → CI pass → `PHASE:awaiting_review` →
 review feedback → address + re-signal → merge → gardener-run.sh executes
-manifest actions via API → `PHASE:done`. On `PHASE:escalate`: session killed
-immediately.
+manifest actions via API → `PHASE:done`. When blocked on external resources
+or human decisions, files a vault item instead of escalating.