chore(hygiene): public-readiness cleanup

- Genericize the only two home-path leaks (`/home/doug/...` → `<repo-root>`) in
  two plan docs (now also on the commit-guard denylist).
- Fix a typo in shipped code: MetaObjectSerializer DATE-case TODO ("somethinf").
- Delete an empty placeholder test (metadata/test/placeholder.test.ts).
- Drop two dead pre-reorg `.gitignore` entries (`typescript/**`; the real paths
  are `server/typescript/**`, already covered).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: dmealing

.gitignore

@@ -23,8 +23,6 @@ __tmp__/
 .vscode/
 
 # Per-language conventions
-typescript/**/dist/
-typescript/**/node_modules/
 server/java/**/target/
 server/typescript/**/dist/
 server/typescript/**/node_modules/

docs/superpowers/plans/2026-05-29-python-pypi-release.md

@@ -43,7 +43,7 @@ These are credential/account steps the assistant cannot do; the user runs them (
 
 Run:
 ```bash
-cd /home/doug/Development/metaobjects
+cd <repo-root>
 cp LICENSE server/python/LICENSE
 ```
 

docs/superpowers/plans/2026-05-30-migration-runner.md

@@ -1041,7 +1041,7 @@ Expected: PASS.
 Run:
 ```bash
 cd server/typescript/packages/migrate-ts && bun test
-cd /home/doug/Development/metaobjects && bun run --filter '@metaobjectsdev/migrate-ts' typecheck
+cd <repo-root> && bun run --filter '@metaobjectsdev/migrate-ts' typecheck
 ```
 Expected: all green (no regressions).
 

server/java/metadata/src/main/java/com/metaobjects/io/object/gson/MetaObjectSerializer.java

@@ -73,7 +73,7 @@ protected void writeField(MetaObject mo, MetaField mf, Object vo,
                 jsonObject.addProperty(name, mf.getInt(vo));
                 break;
 
-            case DATE:      // TODO: should we do somethinf custom here?
+            case DATE:      // TODO: consider custom DATE serialization
                 jsonObject.add(name, context.serialize(vo));
                 break;