feat: patterns/ directory + skill-impact tracker (WikiSkill-inspired)

- New patterns/ directory with 7 initial failure-mode patterns (PAT-001..007)
- skill-impact.md audit trail for skill modifications
- _template.md for future pattern creation
- index.md updated with Patterns section
- log.md entry for this change
- Inspired by arXiv:2608.27454 (WikiSkill)

patterns/linkedin-react-input.md

@@ -0,0 +1,58 @@
+---
+pattern_id: PAT-006
+title: "LinkedIn login via browser — nativeInputSetter required, session expires between nav"
+category: integration
+severity: medium
+status: active
+first_observed: 2026-07
+last_updated: 2026-08-30
+related_systems: []
+related_solution_docs:
+  - docs/solutions/bug-fixes/2026-07-10-ha-token-expiry-browser-session-loss.md
+related_skills: [linkedin-personal-branding]
+---
+
+# LinkedIn login via browser — nativeInputSetter required, session expires between nav
+
+## Symptom
+
+Automated LinkedIn login via browser tools fails silently. Form fields appear filled
+but LinkedIn doesn't recognize the input (login button stays disabled, or submission
+fails with "invalid credentials").
+
+Additionally, authenticated sessions expire between page navigations, requiring
+re-login on almost every navigation step.
+
+## Root Cause
+
+1. **React-controlled inputs**: LinkedIn uses React, which manages input state internally.
+   Simply setting `.value` via DOM manipulation doesn't trigger React's onChange handler.
+   The `nativeInputSetter` approach is required:
+   ```javascript
+   const setter = Object.getOwnPropertyDescriptor(
+     window.HTMLInputElement.prototype, 'value'
+   ).set;
+   setter.call(inputElement, 'my-value');
+   inputElement.dispatchEvent(new Event('input', { bubbles: true }));
+   ```
+
+2. **Session expiry**: LinkedIn's SPA doesn't persist auth tokens reliably across
+   `browser_navigate` calls (each navigation may reset the JS context).
+
+## Mitigation
+
+- Always use `browser_console` with `nativeInputSetter` for form fills — NOT `browser_click`
+  followed by typing
+- Perform login + desired action in a SINGLE browsing session (minimize navigations)
+- UTF-8 files must be saved without BOM (LinkedIn rejects BOM in posted content)
+
+## Prevention
+
+- The `linkedin-personal-branding` skill documents this workflow
+- Never use `browser_click` for LinkedIn form fields
+- Minimize navigation steps after login
+
+## Evidence
+
+- Observed during LinkedIn branding sessions (Jul 2026)
+- MEMORY.md entry: "Login via browser_console nativeInputSetter. NOT browser_click. Session expires between nav. UTF-8 no BOM."