[REFACTOR] Clean up source-management route structure and state

[ksamaschke]

Phase

REFACTOR

## Deliverable
Simplify route structure and state ownership for repository and source-management content after GREEN.

## Dependencies
- Parent work item: #216.

## Completion evidence
- Cleanup notes for source-management route state.

• Evidence that source-management placement remains correct.

  Acceptance criteria

  • Source-management state is easier to extend.

• The cleanup does not push source workflows back into Settings.

  Parent: Work Item: Move repository and source management into route-based content #216

[ksamaschke]

REFACTOR is complete in the dedicated worktree branch codex/216-sources-route-20260315075125.

Cleanup performed:

• separated selected-source publish settings from new-source creation state
• extracted source draft helpers into src/installer-dashboard/web/src/source-management-state.ts
• added focused coverage in tests/installer/source-management-state.test.ts

Validation so far:

• npm run build:quick
• node --test dist/tests/installer/desktop-source-route-red-phase.test.js dist/tests/installer/desktop-shell-ux.test.js dist/tests/installer/desktop-settings-window-red-phase.test.js dist/tests/installer/desktop-sidebar-routes-red-phase.test.js dist/tests/installer/dashboard-source-actions-style.test.js dist/tests/installer/source-management-state.test.js

[ksamaschke]

Completed via PR #255, merged into dev at commit 3464655bc7735e3fc71bb5351146aad0e0813591.

REFACTOR evidence:

• extracted src/installer-dashboard/web/src/source-management-state.ts
• separated selected-source publish draft state from new-source creation state
• added focused coverage in tests/installer/source-management-state.test.ts