feat: YAML pipeline template autocomplete (AzDO + GHA)

- Add scripts/sync_pipeline_templates.py — scans LRU AzDO and GHA template
  repos; outputs unified pipeline_templates_catalog.json (48 templates: 45
  AzDO + 3 GHA)
- Add scripts/template_sources.yml — source config (AzDO alias, GHA org)
- Add pipeline_templates_catalog.json — baked catalog (49 KB)
- Add ilsp/yaml_lsp/catalog.py — PipelineTemplateCatalog with completion item
  generators for template paths, param names, allowed values, GHA inputs
- Add ilsp/yaml_lsp/proxy.py — async WS↔TCP bridge with LSP frame buffering,
  per-connection document tracking, AzDO/GHA context detection, and completion
  injection (LRU items sortText 0_, standard items downgraded to 9_)
- Wire yaml_ws_handler into server.py (replaces raw _ws_proxy call)
- Load PipelineTemplateCatalog at startup; reload + health report template count
- Update push_catalogs.sh to push pipeline_templates_catalog.json
- Update Dockerfile to bake pipeline_templates_catalog.json as image fallback
- Add tests/test_yaml_catalog.py (14 tests) + tests/test_yaml_proxy.py (18 tests)
  All 67 tests green

Dockerfile

@@ -20,6 +20,7 @@ WORKDIR /build
 COPY pyproject.toml .
 COPY ilsp/ ilsp/
 COPY bicep_modules_catalog.json .
+COPY pipeline_templates_catalog.json .
 
 RUN pip install --upgrade pip build \
     && python -m build --wheel --outdir /dist
@@ -43,6 +44,7 @@ COPY --from=bicep-downloader /opt/bicep-langserver /opt/bicep-langserver
 # Install Python package and dependencies
 COPY --from=builder /dist/*.whl /tmp/
 COPY --from=builder /build/bicep_modules_catalog.json /bicep_modules_catalog.json
+COPY --from=builder /build/pipeline_templates_catalog.json /pipeline_templates_catalog.json
 RUN pip3 install --no-cache-dir --break-system-packages /tmp/*.whl && rm /tmp/*.whl
 
 # Configuration defaults (override via Nomad env)