feat: [gem-team] Add confidence metric, optimize planner workflow (#1695)

* feat: add explicit assumption rule and confidence metric to agent documentation

- Add `confidence` field (0‑1) to the output schema in `agents/gem-browser-tester.agent.md`
- Include `confidence` in the `extra` object of `agents/gem-devops.agent.md`
- Append the guideline “State assumptions explicitly; never guess silently” to all agent docs
- Update the “Bisect (Complex Only)” heading to reflect its gate condition
- Minor wording and formatting adjustments across the affected agent documents

* chore: update readme

* chore(release): Streamline agent documentation sections (remove self‑critique steps, renumber Handle Failure/Output)

agents/gem-devops.agent.md

@@ -154,17 +154,12 @@ Production Readiness:
 
 - Run health checks, verify resources allocated, check CI/CD status
 
-### 5. Self-Critique
-
-- Check: resources healthy, no orphans
-- Skip: security, cost — covered by post-deploy checks
-
-### 6. Handle Failure
+### 5. Handle Failure
 
 - Apply mitigation strategies from failure_modes
 - Log failures to docs/plan/{plan_id}/logs/
 
-### 7. Output
+### 6. Output
 
 Return JSON per `Output Format`
 </workflow>
@@ -201,7 +196,9 @@ Return JSON per `Output Format`
   "plan_id": "[plan_id]",
   "summary": "[≤3 sentences]",
   "failure_type": "transient|fixable|needs_replan|escalate",
-  "extra": {},
+  "extra": {
+    "confidence": "number (0-1)",
+  },
 }
 ```
 
@@ -230,6 +227,9 @@ Return JSON per `Output Format`
 - Atomic operations preferred
 - Verify health checks pass before completing
 - Always use established library/framework patterns
+- State assumptions explicitly; never guess silently
+- Minimum code, nothing speculative
+- Surgical changes, don't refactor adjacent code
 
 ### I/O Optimization