feat: add Factory Droid (droid) agent support

[OzeroHAX]

Summary

Adds Factory Droid (droid CLI by Factory AI) as a supported agent in CodeDash — session loading, detail view, preview, replay, search, cost estimation, active detection, and full UI integration.

What changed

• add Droid session discovery from ~/.factory/sessions//*.jsonl with session_start metadata parsing (cwd, sessionTitle) and Claude-compatible message format ({type: "message", message: {role, content:
  [blocks]}})
• load Droid detail into the unified transcript format used by session detail, preview, replay, search, and export paths
• include Droid sessions in active process detection (ps aux grep for droid), cache invalidation (mtime monitoring of ~/.factory/sessions/), and terminal launch/resume (droid --resume )
• extract MCP tool usage from assistant tool_use content blocks using the same extractTools() pipeline as Claude
• expose Droid throughout the UI: sidebar filter with robot icon, green badge (.tool-droid / --accent-green), filter chip, install command (curl -fsSL https://app.factory.ai/cli | sh), and calendar view toggle
• add file-size-based cost fallback for sessions without token usage metadata, using claude-sonnet-4-6 pricing as baseline estimate
• add Droid system message filtering (You are Droid, <factory_config) to isSystemMessage()
• add WSL support with EXTRA_DROID_DIRS for Windows-side ~/.factory detection

Validation

Manual checks run locally against real ~/.factory data (12 sessions across 4 projects):

• node -c src/data.js
• node -c src/terminals.js
• node -c src/frontend/app.js
• node -c src/frontend/calendar.js
• node -e "..." — confirmed 12 Droid sessions loaded with correct project paths, message counts, and session titles
• loadSessionDetail() — verified 32 messages parsed from a real session with correct role/content extraction
• getSessionPreview() — returns 10 preview messages
• computeSessionCost() — returns file-size-based cost estimate
• node bin/cli.js run — dashboard starts cleanly, Droid sessions visible with green badges

Known limitations

• Cost is estimated from file size (no per-turn token usage in Droid JSONL), so cost figures are approximate.
• droid --resume command is assumed but not verified against the actual Droid CLI — may need adjustment to match the real resume flag.
• history.json (JSON array) is not used for session enrichment — all data comes from session JSONL files directly.

[vakovalskii]

Looks good structurally — follows the same pattern as other agents. Will merge after resolving conflicts with recent refactoring (app.js was split into modules in v6.15.5). Please rebase on latest main.

[OzeroHAX]

Rebased on the latest main and force-pushed.

I also resolved the post-refactor integration cleanly against the current frontend layout and fixed a couple of follow-up issues I found while verifying:

• Copy Command now uses droid --resume ...
• droid is now shown correctly in analytics/heatmap
• estimated cost handling is wired in for droid as well

Ready for another pass.