Add /diff and /template commands

- /diff command to compare config with backups
  - Shows added/removed/changed files
  - JSON-aware comparison for config files
  - List available backups
- /template command for session templates
  - Built-in templates: daily-standup, code-review, troubleshoot, deploy
  - Each template includes checklist, initial commands, prompt
  - Create custom templates interactively or non-interactively
- Updated shell completions with 21 aliases total
- Test suite now covers 29 tests

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

state/personal-assistant/templates/daily-standup.json

@@ -0,0 +1,16 @@
+{
+  "name": "daily-standup",
+  "description": "Morning status check and planning",
+  "category": "routine",
+  "context_level": "moderate",
+  "initial_commands": [
+    "/status"
+  ],
+  "checklist": [
+    "Check system health",
+    "Review pending items",
+    "Check calendar",
+    "Plan priorities"
+  ],
+  "prompt_template": "Good morning! Let's start with a quick status check and plan the day."
+}