Add cross-project pattern registry for retrieval-augmented generalization

- Create patterns/ directory with README, manifest, and 10 initial patterns
  covering Ollama JSON fallback, API escaping, deprecation, PTY auth,
  queue-poll, LLM-as-parser, credential rotation, reverse proxy binding,
  human approval gates, and transient retry.
- Wire pattern loading into architecture/pipeline.js based on task tags.
- Update architecture/orchestrator.js to load patterns and surface them in
  the system prompt.
- Update MEMORY.md, ARCHITECTURE.md, and CONTEXT.md to document the registry
  and record the decision.

patterns/api-version-deprecation.md

@@ -0,0 +1,29 @@
+# Pattern: API Version Deprecation
+
+## Symptom
+An integration that worked yesterday starts returning 400/401/404 or generic errors. Vendor documentation mentions an older API version is deprecated or sunset. Calls using the old version silently stop working or return migration messages.
+
+## Affected Projects
+- LinkedIn content automation (LinkedIn REST API version deprecation)
+
+## Root Cause
+External SaaS APIs version their endpoints and periodically retire old versions. Hard-coded version strings in workflows or apps become liabilities when the vendor changes the supported window.
+
+## Standard Fix
+1. Record the API version in use at design time, plus where to check for deprecation notices (vendor developer portal, changelog, email alerts).
+2. Centralize API version strings in environment variables or config, not scattered through code.
+3. Subscribe to vendor developer changelogs or status pages.
+4. Plan version migration as a tracked task rather than an emergency fix.
+5. Add a lightweight health check that verifies the integration still responds with expected schema/version fields.
+
+## When to Apply
+- Every new external API integration.
+- Any existing integration that has no documented API version or deprecation monitoring.
+
+## Verification
+- Vendor docs show the version is current and supported.
+- Health check returns expected version/schema fields.
+- A deprecation monitoring source is identified and checked.
+
+## Related Patterns
+- `credential-rotation-recovery`