Feature/diff status

[pankajackson]

This PR adds two core commands to dotctl:

• dotctl status → shows system health, profile state, config status, and drift summary
• dotctl diff → shows differences between local system files and stored profile

These improve visibility into configuration drift and system state.

---

Features

dotctl status

Provides a structured overview of:

• Profile health (git repo, active branch, remote)
• Config validation status
• Drift summary (modified, missing, synced files)
• --json and --short output modes

Example:

✔ profile: ok
✔ config: ok
ℹ active profile: desktop_main

✔ system: in sync
✔ synced files: 2
✔ modified files: none
✔ missing files: none

---

dotctl diff

Shows file-level differences between local system and profile.

Supports:

• Full diff
• Single file target
• --color output
• --side-by-side view

Example:

🔍 diff: configs/test.txt
--- repo
+++ local
@@ -1,3 +1,4 @@
 line 1
+new line
 line 2

---

Design Notes

• Separated logic into:

  • profile collection
  • config validation
  • drift detection
  • rendering layer

• Introduced structured StatusReport for better maintainability

• Error handling ensures CLI never crashes unexpectedly

• Consistent icon usage for status output

---

Checklist

• status command implemented
• diff command implemented
• JSON + short output support
• side-by-side diff
• structured status model
• error-safe execution