[codex] Move routing rules into workspaces

[revitteth]

Summary

• Add /workspaces/routes as the primary home for routing configuration, with Advanced/config route aliases redirecting there while preserving query params.
• Promote routing under Workspaces navigation and copy, and make Workspace Routing expose Add server, Add rule, and Reload actions directly.
• Move command-palette and related links from Advanced routes to Workspace routes.
• Remove generated internal/web/dist output from git completely: no hashed assets, no sentinel file. Generated assets are ignored, clean targets delete the directory, and build/install paths generate the dashboard before Go binaries are compiled.
• Make clean-checkout Go tooling compile without internal/web/dist while still embedding the generated dashboard whenever the web build has produced it.

Validation

• Browser smoke: /workspaces/routes renders Workspace Routing and Add rule; /advanced/routes?workspace=... redirects to /workspaces/routes?workspace=....
• rm -rf internal/web/dist && git ls-files internal/web/dist && go test ./internal/api
• rm -rf internal/web/dist && go test ./...
• cd web && npm run build
• git check-ignore -v internal/web/dist internal/web/dist/index.html internal/web/dist/assets/index-cLkyy6t-.js
• cd web && npm run lint (0 errors; existing warnings only)
• cd web && npm run test (23 files / 163 tests passed)
• task build
• go test -tags p2p ./internal/p2p/...
• bash scripts/test-install.sh (uses an isolated random local port and verifies dashboard response from the newly built binary)

Notes

• Local Node is v23.11.0, so npm reports the project engine warning (^20.19.0 || ^22.12.0 || >=24.0.0), but the commands above passed.