fix(agents): remove review-cycle details from CHANGELOG.md [Unreleased] section

Consolidate the ### Fixed entries describing internal PR #11015
review cycle details into a single expanded ### Added entry for
Implementation Pool Supervisor. This follows Keep a Changelog
format where changelog entries describe user/operator-facing
changes, not code review back-and-forth.

- Merged two duplicate ### Fixed sub-headers (review cycle entries)
  into the existing ### Added section
- Removed: 'PR Compliance Checklist now embedded...' entry
- Removed: 'YAML frontmatter fields added...' entry
- Expanded Implementation Pool Supervisor entry to mention that
  workers receive checklist via prompt template and that model/
  reasoningEffort frontmatter are specified

ISSUES CLOSED: #11015

CHANGELOG.md

@@ -104,6 +104,11 @@ Changed `wf10_batch.robot` to be less likely to create files, and
   8-item PR Compliance Checklist (CHANGELOG.md update, CONTRIBUTORS.md update,
   commit footer, CI verification, BDD tests, Epic reference, label application,
   milestone assignment) that workers must complete before creating any PR.
+  The checklist is also embedded verbatim in the prompt template passed to
+  `implementation-supervisor` so workers receive it during dispatch. YAML
+  frontmatter specifies `model: "CleverThis-8/Qwen3-Coder-Next-GGUF-Q6-K"`
+  and `reasoningEffort: "high"`, matching the convention used by other
+  supervisor agents.
 
 ### Fixed
 - **Guard cleanup_stale against execute/processing and execute/complete plans** (#11121):
@@ -158,11 +163,6 @@ Changed `wf10_batch.robot` to be less likely to create files, and
   available, and a `_FallbackPromptInput` otherwise. Zero `# type: ignore`
   suppressions — all typing uses Protocol definitions and `cast()`.
 
-- **PR Compliance Checklist now embedded in `implementation-pool-supervisor` prompt template** (#10069): The supervisor prompt passed to the inner `implementation-supervisor` now includes the full 8-item PR Compliance Checklist verbatim, so workers always receive it during dispatch. Previously only the checklist definitions existed as doc sections but were never injected into the actual worker prompt — identified and fixed in review of PR #11015 by HAL9001.
-
-- **YAML frontmatter fields added to `implementation-pool-supervisor` agent definition** (#10069): Added `model: "CleverThis-8/Qwen3-Coder-Next-GGUF-Q6-K"` and `reasoningEffort: "high"` to the YAML frontmatter, matching the convention used by other supervisor agents (`implementation-supervisor.md`, `pr-merge-supervisor.md`).
-
-
 - **ReactiveEventBus.emit() exception handler** (#988): Fixed the exception handler to log the full exception message (`str(exc)`) and enable traceback forwarding (`exc_info=True`). Previously the handler logged only the exception type name (e.g. "ValueError") with no diagnostic detail. The handler now includes the error message text and full traceback in the structlog warning entry. Removed `@tdd_expected_fail` tag from the TDD test so both scenarios run as normal regression guards.
 - **Actor CLI NAME argument made optional, derived from YAML config** (#4186): The
   `agents actor add` positional `NAME` argument is now optional (defaults to