Use mempalace-mcp entry point directly, drop redundant wrapper

The mempalace Python package ships a 'mempalace-mcp' console entry
point; 'uv tool install' places it on PATH as a shim whose shebang
points at the isolated venv's Python. Our hand-rolled wrapper at
/usr/local/bin/mempalace-mcp-server was duplicating what uv installs
for free — one less file to maintain.

Fixes the MCP error users saw after the v1.14.28b → v1.14.29 upgrade
path: custom opencode.json files typically had the pre-v1.14.29
command ['python3', '-m', 'mempalace.mcp_server'] which worked with
the old pip install but fails silently after the uv-tool migration
because system python3 cannot import from the venv. Opencode surfaced
this as 'MCP error -32000: connection closed'.

- generate-config.py now emits ['mempalace-mcp'] and keys its detect
  on shutil.which('mempalace-mcp').
- Dockerfile drops 'COPY rootfs/usr/local/bin/' and the chmod of the
  wrapper. Build shrinks from 30 to 29 stages.
- rootfs/usr/local/bin/ removed entirely.
- Smoke test asserts /usr/local/bin/mempalace-mcp is executable and
  prints its symlink target.
- README's MemPalace section shows ['mempalace-mcp'] and explicitly
  warns against the old pattern with the observed failure mode.
- CHANGELOG adds a v1.14.29c entry.

AGENTS.md

@@ -9,8 +9,7 @@ Docker image packaging [opencode](https://opencode.ai) into a production-ready d
 - `Dockerfile` — single multi-stage build for both variants. OMOS variant is controlled by `INSTALL_OMOS=true` build arg; mempalace is controlled by `INSTALL_MEMPALACE` (default `true`). All GitHub-sourced binaries are pinned with version ARGs.
 - `entrypoint.sh` — runs as root: UID/GID adjustment, SSH permissions, volume ownership fixes (skipped via `.devbox-owner` sentinel when ownership is already correct). Then drops to developer via gosu.
 - `entrypoint-user.sh` — runs as developer: git config, opencode.json generation (delegated to `generate-config.py`), OMOS setup.
-- `rootfs/usr/local/lib/opencode-devbox/generate-config.py` — generates `~/.config/opencode/opencode.json` from env vars. Never overwrites an existing config. Auto-registers MCP servers for detected tools (mempalace via the wrapper, gitea-mcp).
-- `rootfs/usr/local/bin/mempalace-mcp-server` — wrapper that exec's the mempalace uv-tool venv's python with `-m mempalace.mcp_server`. Needed because system `python3` can't import from the isolated venv created by `uv tool install`.
+- `rootfs/usr/local/lib/opencode-devbox/generate-config.py` — generates `~/.config/opencode/opencode.json` from env vars. Never overwrites an existing config. Auto-registers MCP servers for detected tools (mempalace via the `mempalace-mcp` entry point, gitea-mcp).
 - `scripts/smoke-test.sh` — post-build image verification. Asserts binary presence, opencode startup, entrypoint correctness, config generation idempotency, and image size thresholds. Used by both CI workflows.
 - `scripts/generate-dockerhub-md.py` — generates `DOCKER_HUB.md` from `README.md` using explicit section rules. `--check` fails if the committed file is out of sync (enforced by the `validate` workflow).
 - `DOCKER_HUB.md` — **auto-generated** from README. Do not edit directly. Pushed to Docker Hub description via CI API call. Must stay under 25 kB. Short description field must be ≤100 bytes.
@@ -38,7 +37,7 @@ When bumping the opencode version, also bump `OPENCODE_VERSION` in `Dockerfile`
 - **GitHub/Gitea-sourced binaries float by default** — gosu, fzf, git-lfs, nvim, bat, eza, zoxide, uv, gitea-mcp, Go, oh-my-opencode-slim all default to `latest`. Each build-time install step reads the `/releases/latest` Location redirect (or the go.dev JSON feed for Go) and derives the concrete version. Use the same `ARCH` case-switch pattern for multi-arch support (amd64/arm64). Intentional pins: `OPENCODE_VERSION` (drives the image tag), `NODE_VERSION=22` (major pin), `DEBIAN_VERSION=trixie-slim` (OS base). Adding a new upstream tool: follow the existing floated-version pattern, don't hardcode a specific tag.
 - **Resolved versions are logged by the smoke test** — `scripts/smoke-test.sh` prints a "Resolved component versions" table as its first step. CI logs always capture what got baked into a given image even when ARGs default to `latest`.
 - **Shell scripts use `set -euo pipefail`** — both entrypoints are strict. Errors in volume chown or SSH permission operations are intentionally suppressed with `|| true`.
-- **MemPalace install path** — installed via `uv tool install` into `/opt/uv-tools/mempalace/`. The `mempalace` CLI is symlinked onto `PATH` by uv; the MCP server is reached via the `mempalace-mcp-server` wrapper. Do not use `pip install --break-system-packages` — that was the previous approach and has been removed.
+- **MemPalace install path** — installed via `uv tool install` into `/opt/uv-tools/mempalace/`. Both the `mempalace` CLI and the `mempalace-mcp` MCP server binary are shipped as entry points by the mempalace package itself and placed on PATH by uv as shims whose shebangs point at the venv's Python. No hand-rolled wrapper is needed. Do not use `pip install --break-system-packages` — that was the previous approach and has been removed. Do not use `["python3", "-m", "mempalace.mcp_server"]` in `opencode.json` — system Python can't import from the uv venv.
 - **generate-config.py idempotency** — the script MUST never overwrite an existing `opencode.json`. Users bind-mount their config directory or persist it across container recreations; accidentally clobbering that file would destroy hand-edits. The smoke test asserts this.
 - **Docker Hub description update** — uses `/v2/auth/token` endpoint (not the deprecated `/v2/users/login`). Auth uses `identifier`/`secret` fields, returns `access_token`, sent as `Bearer`. Short description must be ≤100 bytes.