scaffold: project structure, wire contract, roadmap and agent briefs

Lays out Velox Download Manager (IDM-class download manager for Ubuntu
26.04) as a monorepo ready for parallel lane development. No implementation
code by design.

- docs/: architecture, roadmap M0-M7, IDM-parity GUI spec, engine design,
  Firefox extension spec, risks/spikes, packaging
- contracts/: wire-contract skeleton (JSON Schema + fixture templates) —
  the single synchronization point between lanes
- docs/agents/: one brief per lane (PROTO, CORE, DAEMON, GUI, EXT, PKG/QA)
  with owned directories, build order and definition of done
- CLAUDE.md: rules of engagement — lane ownership, layering, non-negotiables
- CMake scaffolding with dev/tsan/release/ci presets

Two environment findings shape the design: Firefox here is the Mozilla snap
(native-messaging risk, so the extension carries a loopback-WebSocket
fallback), and Wayland forbids passive clipboard monitoring (so clipboard
capture is explicit-action-first).

Co-Authored-By: Claude Opus 5 <[email protected]>

.gitignore

@@ -0,0 +1,15 @@
+build/
+.cache/
+compile_commands.json
+node_modules/
+dist/
+web-ext-artifacts/
+*.o
+*.so
+*.a
+*.log
+.venv/
+__pycache__/
+.DS_Store
+*.veloxpart
+*.veloxpart.meta