chore: remove internal dev docs from tracking, clean branding, harden .gitignore

- Removed 23 internal dev docs from git tracking (PHASE specs, audits, reports)
- Added all internal docs to .gitignore
- Removed last 'webclaw' reference from source code
- Added dist/ and research/ to .gitignore
- No secrets found in source (verified .env.example, diagnostics.ts)

.gitignore

@@ -88,3 +88,19 @@ tmp/
 
 # Task data (local persistence)
 data/
+dist/
+research/
+BROWSER-RESEARCH.md
+CHAT-TEST-REPORT.md
+DEVELOPMENT-STATUS.md
+FEATURE-AUDIT.md
+PHASE_5_REVIEW.md
+PR_SUMMARY_4.3.md
+RELEASE_NOTES_v2.1.2.md
+COMPETITOR-ANALYSIS.md
+SECURITY-AUDIT.md
+docs/PHASE-*
+docs/DASHBOARD_FINALIZATION_PLAN.md
+docs/MODEL_SWITCHER_AUDIT.md
+docs/MODEL_SWITCHER_TESTPLAN.md
+docs/OVERNIGHT-SHIP-REPORT.md