docs(changelog): update CHANGELOG.md and documentation for recent merged features

- Add [Unreleased] section entries for recent merged PRs:
  - Fixed: project delete deleted_at output (#6314)
  - Changed: grooming agent rename (backlog-groomer → groomer)
- Restructure [Unreleased] to proper Keep a Changelog order (Added/Changed/Fixed)
- Update README.md with Active Milestones section (v3.2.0–v3.5.0)
- Addresses documentation gap identified in issue #9310

CHANGELOG.md

@@ -5,16 +5,6 @@ The format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
 ## [Unreleased]
 
-### Fixed
-
-- **Automation Profile Silent Fallback** (#8232): `_resolve_profile_for_plan` in
-  `PlanLifecycleService` now raises a clear `ValidationError` when a plan's
-  automation profile name is not a known built-in profile, instead of silently
-  falling back to `"manual"`. Users who configured custom automation profiles
-  (e.g. `"semi-auto"`, `"acme/strict"`) will now receive an actionable error
-  message listing available built-in profiles. The resolved profile name is also
-  logged at debug level for observability.
-
 ### Added
 
 - **TDD Issue-Capture Test Activation** (#7025): Replaced 234 bare `@skip` tags
@@ -112,6 +102,12 @@ The format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
 ### Changed
 
+- **Grooming Agent Rename**: The `backlog-grooming-pool-supervisor` agent has
+  been renamed to `grooming-pool-supervisor` (and `backlog-groomer` to
+  `groomer`) to better reflect its expanded scope beyond backlog management.
+  The tier selector dispatch was also fixed to correctly route to the renamed
+  agent. All internal references have been updated.
+
 - **Decision Tree Full ULID Display** (#5825): The `agents plan tree` command now
   displays full 26-character ULIDs for all decisions instead of truncating them to
   8 characters. This enables users to copy decision IDs directly from tree output
@@ -143,6 +139,20 @@ The format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
 ### Fixed
 
+- **Project Delete `deleted_at` Output** (#6314): `agents project delete` now
+  includes the `deleted_at` timestamp in both JSON and YAML output formats,
+  giving callers a machine-readable confirmation of when the project was
+  removed. Previously the field was silently omitted, requiring a separate
+  `agents project show` call to confirm deletion time.
+
+- **Automation Profile Silent Fallback** (#8232): `_resolve_profile_for_plan` in
+  `PlanLifecycleService` now raises a clear `ValidationError` when a plan's
+  automation profile name is not a known built-in profile, instead of silently
+  falling back to "manual". Users who configured custom automation profiles
+  (e.g. "semi-auto", "acme/strict") will now receive an actionable error
+  message listing available built-in profiles. The resolved profile name is also
+  logged at debug level for observability.
+
 - **Plan Concurrency Race Condition** (#7989): Fixed critical race condition in `execute_plan()` and
   `apply_plan()` where concurrent CLI/worker sessions could simultaneously modify the same plan,
   corrupting plan state. `LockService` is now wired into the plan lifecycle with plan-level advisory

README.md

@@ -105,6 +105,19 @@ agents server connect --url https://my-server.example.com --token <TOKEN>
 agents server status
 ```
 
+## Active Milestones
+
+The following milestones are currently under active development:
+
+| Milestone | Status | Focus |
+|-----------|--------|-------|
+| v3.2.0 | Active | Decisions, validations, invariants, automation profiles |
+| v3.3.0 | Active | Corrections, subplans, checkpoint/rollback, decision tree versioning |
+| v3.4.0 | Active | ACMS v1, resource type inheritance, safety profile extraction |
+| v3.5.0 | Active | Autonomy hardening, resource DAG, container/LSP resource types |
+
+See [Implementation Timeline](docs/timeline.md) for detailed schedule adherence tracking.
+
 ## Developing
 
 Pre-commit hooks run automatically on every `git commit` (formatting, linting, type