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.

CHANGELOG.md

@@ -6,6 +6,15 @@ Tags follow `v{opencode_version}[letter]` — bare tag for the first build on a
 
 ---
 
+## v1.14.29c — 2026-04-29
+
+**Drop redundant mempalace-mcp-server wrapper, use the entry point mempalace ships.**
+
+- **Fix:** MCP integration with mempalace was still broken for users with custom `opencode.json` files because they typically had `["python3", "-m", "mempalace.mcp_server"]` from v1.14.28b and earlier. With the uv-tool install path, system python3 can't import mempalace and the MCP server subprocess exits immediately — opencode surfaced this as `MCP error -32000: connection closed`. Users should migrate to `["mempalace-mcp"]`. The auto-generated config in new containers already emits the new form.
+- **Cleanup:** Remove the hand-rolled `/usr/local/bin/mempalace-mcp-server` 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. The wrapper was duplicating what uv installs for free. Removed `rootfs/usr/local/bin/` and its COPY + chmod lines from the Dockerfile.
+- **Docs:** README's MemPalace section now shows `["mempalace-mcp"]` and explicitly warns against `["python3", "-m", "mempalace.mcp_server"]` with the observed failure mode.
+- **Tests:** Smoke test asserts `/usr/local/bin/mempalace-mcp` is executable and prints its symlink target, replacing the previous wrapper-present check.
+
 ## v1.14.29b — 2026-04-29
 
 **Fix OMOS `bunx` detection + CI build reliability.**