docs: add missing hook events from official CHANGELOG (v2.1.9-v2.1.10)

- Add 3 missing events to Section 7.1: Setup, PermissionRequest, SubagentStop
- Document PreToolUse additionalContext feature (v2.1.9+)
- Create 3 production-ready hook templates (setup, permission, subagent)
- Add resource evaluation documenting rejection of secondary source

Source: Official Claude Code CHANGELOG, not external blog posts
Closes gap identified during resource evaluation process

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

guide/ultimate-guide.md

@@ -5992,6 +5992,9 @@ Hooks are scripts that run automatically when specific events occur.
 | `SessionStart` | Session begins | Initialization |
 | `SessionEnd` | Session ends | Cleanup |
 | `Stop` | User interrupts | Graceful shutdown |
+| `Setup` | Claude Code starts | Initialization (v2.1.10+) |
+| `PermissionRequest` | Permission dialog appears | Custom approval logic |
+| `SubagentStop` | Sub-agent completes | Subagent cleanup |
 
 ### Event Flow
 
@@ -6114,6 +6117,16 @@ Hooks can return JSON on stdout:
 }
 ```
 
+**PreToolUse additionalContext** (v2.1.9+): PreToolUse hooks can inject context into Claude's prompt via `additionalContext`. This allows enriching Claude's understanding before tool execution:
+
+```json
+{
+  "hookSpecificOutput": {
+    "additionalContext": "Current git branch: feature/auth. 3 uncommitted files."
+  }
+}
+```
+
 ### Exit Codes
 
 | Code | Meaning | Result |