macOS: first file-edit step triggers a cascade of TCC permission prompts outside project scope

**What happened**

On the very first operation step -- which should only edit files under a user-provided project path -- macOS surfaced six sensitive permission prompts in sequence:
1. Apple Music / music-video activity / media library
2. Files managed by OneDrive
3. Files managed by iCloud Drive
4. Data from other apps
5. Documents folder
6. Downloads folder

Only the Documents/Downloads prompts are arguably justified (the agent may be looking for files). The Apple Music / media-library and cross-app prompts have no business being triggered by a file-editing step and look spurious.

**Likely cause**
The brain does broad filesystem probing well outside the project directory. The same session's shell shows wide scans like `find /usr /opt ~ ...`, walking `~/opt/anaconda3`, and enumerating conda envs -- exactly the kind of reach that trips macOS TCC gates. Likely the same root behavior as #224 (out-of-project reads), surfacing here as a macOS-specific prompt cascade.

**Expected vs actual**
- Expected: a step scoped to the project path triggers at most the prompts needed for that path; no media-library / cross-app prompts.
- Actual: six prompts including media library and OneDrive/iCloud, with no explanation of why each is needed.

**Suggestions**
- Constrain filesystem access to the approved project directory (ties to #224).
- Audit Electron entitlements so the app doesn't request media-library access at all.
- If a probe genuinely needs Documents/Downloads, explain why inline before the OS prompt.

Related: #224 (reads outside project dir without approval).

**Sysinfo:** Orbit 0.3.1 - darwin/arm64 - electron 41.2.1 - model claude-sonnet-4-6 (anthropic)