docs: v0.10.0 release notes (CHANGELOG + README) + version bump

- harness_manager/__init__.py: __version__ bumped to 0.10.0 (was 0.9.0,
  never bumped during the v0.9.1 patch release — fixing now).
- CHANGELOG.md: full 0.10.0 entry covering both the design-md skill (PR #21
  by @danielfoch) under "Added" and the Python 3.9 PEP 604 fix (#27 by
  @WhoLsJohnGalt) under "Fixed".
- README.md: replaces the v0.9.1 "New in" block with v0.10.0 highlights;
  demotes v0.9.1 to a one-line summary.

Author: codejunkie99

CHANGELOG.md

@@ -5,6 +5,55 @@ All notable changes to this project.
 The format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and the project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.10.0] — 2026-04-26
+
+Minor release. Adds the `design-md` seed skill (sixth seed skill in the
+brain), and fixes a hard crash on macOS-default Python 3.9 that hit every
+brew user on first run.
+
+### Added
+- **`design-md` seed skill — DESIGN.md / Google Stitch support.** A new
+  portable skill that points coding agents at a root `DESIGN.md` (Google
+  Stitch format) as the visual-system source of truth. Loads only when
+  `DESIGN.md` exists at the project root; default behavior is read-only on
+  the contract file, and validation prefers
+  `npx @google/design.md lint DESIGN.md` over hand-checks. Brings the seed
+  skill count from five to six. Thanks to @danielfoch for the contribution
+  (PR #21). Decision recorded in `.agent/memory/semantic/DECISIONS.md`.
+
+### Fixed
+- **Python 3.9 crash on first run (#27).** Every brew user on macOS-default
+  Python 3.9 hit `TypeError: unsupported operand type(s) for |: 'type' and
+  'type'` immediately after `brew install agentic-stack` because
+  `harness_manager/` used PEP 604 union syntax (`Path | str`) that requires
+  Python 3.10+ at runtime. Added `from __future__ import annotations`
+  (PEP 563) to the eight affected files so all annotations are stored as
+  strings and never evaluated at import time. Works on Python 3.7+, which
+  covers every macOS-shipped Python in the wild. Zero-cost vs. the
+  reporter's suggested `python@3.10` brew dep (~150 MB pull). Thanks to
+  @WhoLsJohnGalt for the precise repro and the suggested workaround.
+
+### Migration
+`brew upgrade agentic-stack` is enough — no on-disk schema changes. Users
+on Python 3.9 who hit #27 on v0.9.x can upgrade and the crash goes away.
+Users with existing `.pi/extensions/memory-hook.ts` from v0.9.0 already
+got the fixes via `./install.sh pi` after the v0.9.1 upgrade; this release
+adds the `design-md` skill on top.
+
+### Release
+- Tag `v0.10.0` cut from master.
+- GitHub release: <https://github.com/codejunkie99/agentic-stack/releases/tag/v0.10.0>
+- `Formula/agentic-stack.rb` bumped to v0.10.0 in a follow-up commit
+  (same flow as v0.8.0 → v0.9.0 → v0.9.1): tag first, compute sha256,
+  then bump `url` + `sha256` + `version` together so brew always points
+  at a real installable artifact.
+
+### Credits
+- PR #21 by @danielfoch (design-md skill), with cross-model review fixes
+  applied as a follow-up commit.
+- Issue #27 by @WhoLsJohnGalt — clean repro of the macOS Python 3.9 crash
+  including a working sed-based workaround.
+
 ## [0.9.1] — 2026-04-26
 
 Patch release that closes the gap between v0.9.0 and a working pi adapter.

README.md

@@ -12,27 +12,31 @@ A portable `.agent/` folder (memory + skills + protocols) that plugs into Claude
   <img src="docs/diagram.svg" alt="agentic-stack architecture" width="880"/>
 </p>
 
-### New in v0.9.1 — pi adapter fixes + tz correctness
-
-Patch release. Closes the gap between v0.9.0 and a working pi adapter,
-plus a timezone sweep across every Python writer/reader so the dream
-cycle stops drifting against the UTC decay window.
-
-- Brew users on v0.9.0 hit `ModuleNotFoundError: harness_manager` on
-  first run. Formula now installs `harness_manager/` correctly.
-- Pi's dream cycle never fired (`session_shutdown` filter rejected every
-  event because `SessionShutdownEvent` has no `reason` field). Now runs.
-- Pi's edit reflections were missing the diff (hook expected MultiEdit
-  shape; Pi's edit input is flat). Now captures `oldText` / `newText`.
-- Naive-local Python timestamps reinterpreted at decay time as UTC
-  caused silent drift. Every writer now emits aware UTC; every reader
-  normalises naive entries before comparing.
-- `auto_dream` held no lock across its read-modify-write window —
-  concurrent appenders could be silently truncated. Now holds a single
-  `flock(LOCK_EX)` on the episodic log for the full cycle.
+### New in v0.10.0 — design-md skill + Python 3.9 fix
+
+Minor release. Adds a sixth seed skill and unbreaks `brew install` for
+every macOS user on the system Python.
+
+- **`design-md` seed skill.** Drop a Google Stitch-style `DESIGN.md` in
+  your project root and the skill points coding agents at it as the
+  visual-system source of truth — colors, typography, spacing, components,
+  rationale. Loads only when `DESIGN.md` exists; default behavior is
+  read-only on the contract file.
+- **Python 3.9 crash on first run is fixed (#27).** Every brew user on
+  macOS-default Python 3.9 hit `TypeError: unsupported operand type(s) for
+  |: 'type' and 'type'` immediately after install. Root cause: PEP 604
+  union annotations (`Path | str`) that require Python 3.10+. Fixed by
+  adding `from __future__ import annotations` to the eight affected
+  `harness_manager/` files; works on Python 3.7+.
 
 See [CHANGELOG.md](CHANGELOG.md) for the full list.
 
+### v0.9.1 — pi adapter fixes + tz correctness
+
+Closed the gap between v0.9.0 and a working pi adapter, plus a timezone
+sweep across every Python writer/reader so the dream cycle stops drifting
+against the UTC decay window.
+
 ### v0.9.0 — harness manager
 
 <p align="center">

harness_manager/__init__.py

@@ -5,4 +5,4 @@
 The "harness_manager" name is internal only and never appears in CLI help, docs,
 or error messages users see.
 """
-__version__ = "0.9.0"
+__version__ = "0.10.0"