fix(v1.2.0): 25 bug fixes, README rewrite, version bump

[victormartingil]

Summary

• 25 bug fixes across the codebase (6 critical, 12 important, 7 quality improvements)
• README completely rewritten — cleaner design, honest positioning, focused on developers/architects
• Version bumped to 1.2.0

Critical Fixes

• REPL input line duplication on render (cursor row tracking)
• Bracketed paste mode not restored on process exit
• SIGINT handler scoping error causing TypeScript build failure
• Path traversal vulnerability in read_image tool
• ReDoS vulnerability in grep_search regex
• Snapshot restore using shallow copy (shared references after rollback)

Important Fixes

• ANSI-safe text wrapping in renderer (code blocks with escape codes)
• Streaming indicator cleanup leak in renderCodeBlock
• Diff-renderer path parsing and zero-width terminal crash
• Confirmation dialog raw mode restore
• deepMergeConfig missing optional sections (stack, mcp, tools, integrations)
• Invalid convergenceThreshold cross-unit validation removed
• Silent JSON parse failures in Anthropic/OpenAI providers now logged
• Gemini tool call dedup non-determinism (sorted keys)
• Phase transition validation enforcing COCO ordering
• Atomic state save (temp file + rename pattern)

Quality Improvements

• Terminal resize handler (SIGWINCH) for input
• Standardized quality evaluator fallback values
• Missing 5 dimensions added to regression test helper
• Improved Gemini token counting heuristic
• Diff-renderer formatLineNo padding fix
• Trust settings save failures now logged
• Lint warnings fixed in search.ts regex

Test plan

• pnpm typecheck — 0 errors
• pnpm lint — 0 errors (1 pre-existing warning: intentional ANSI control regex)
• pnpm test — 171 files, 4352 tests passing, 0 failures
• All new/updated tests for path traversal, phase transitions, atomic save, and image tests pass
• Version reads correctly as 1.2.0

Versioning

After merging, tag with v1.2.0:

git tag v1.2.0
git push origin v1.2.0