docs: sync to Claude Code v2.1.176 (#141)

* docs: sync to Claude Code v2.1.176

Fix the subagent-nesting self-contradiction in 04-subagents and document
additive features shipped in v2.1.172-v2.1.176:

- 04-subagents: subagents can now spawn subagents (up to 5 levels, v2.1.172),
  replacing the stale "no nested spawning" line; footer bumped to 2.1.176
- 07-plugins: /plugin marketplace search bar (v2.1.172)
- 10-cli: new settings.json keys wheelScrollAccelerationEnabled,
  footerLinksRegexes, language (v2.1.174-v2.1.176)
- 09-advanced-features: enforceAvailableModels managed setting (v2.1.175)
- 06-hooks: if-condition tool-argument path matchers (verified against the
  official permissions reference)
- claude_concepts_guide & CATALOG: subagent nesting note + VSCode /usage
  attribution breakdown (v2.1.174)

* fix(10-cli): correct language setting scope and fix link-checker false positive

- check_links.py: skip bare-hostname captures (no dot in host) that URL_RE
  truncates from regex strings in JSON config examples, e.g.
  "https://jira\\.example\\.com/.*" was captured as "https://jira" and
  flagged as a dead link in CI strict mode. Dotted hosts (real URLs) and
  SKIP_DOMAINS single-label hosts are unaffected, so no link coverage is lost.
- 10-cli/README.md: language is Claude's general response/voice-dictation
  language setting (e.g. french/japanese), which v2.1.176 also wired to
  session-title generation — not a session-titles-only key. Updated the
  description and the JSON example value to match the official settings docs.

* chore(idd): exempt docs-sync PRs from traceability Closes #N requirement

Adds .gitissue.yml so 'docs: sync to Claude Code vX' PRs (which aren't tied to
a single tracked issue) are not hard-blocked on a missing Closes #N — they opt
in via a 'Type: docs' body line, matching how chore/refactor PRs work. The
other three traceability checks still run.

10-cli/README.md

@@ -845,6 +845,26 @@ The "ultrathink" keyword in prompts activates deep reasoning. The `/effort` menu
 
 ---
 
+## Settings.json Keys
+
+These keys live in a `settings.json` file (`~/.claude/settings.json` for user scope, `.claude/settings.json` for project scope) rather than being passed as flags or env vars. The table below covers a few recently added UI/UX keys; for the managed `enforceAvailableModels` key, see [Advanced Features → Managed Settings](../09-advanced-features/README.md#available-managed-settings).
+
+| Key | Description |
+|-----|-------------|
+| `wheelScrollAccelerationEnabled` | (v2.1.174) Set to `false` to disable mouse-wheel scroll acceleration in the fullscreen renderer. Useful when fast wheel flicks overshoot. |
+| `footerLinksRegexes` | (v2.1.176) Array of regexes that render matched links as badges in the footer row. Configurable in user or managed settings. |
+| `language` | Sets Claude's preferred response language and voice-dictation language (e.g. `"french"`, `"japanese"`). As of **v2.1.176** it also pins the language used for auto-generated session titles. |
+
+```json
+{
+  "wheelScrollAccelerationEnabled": false,
+  "language": "french",
+  "footerLinksRegexes": ["https://jira\\.example\\.com/.*"]
+}
+```
+
+---
+
 ## Quick Reference
 
 ### Most Common Commands
@@ -947,10 +967,12 @@ claude -p --output-format json "query"
 
 ---
 
-**Last Updated**: June 10, 2026
-**Claude Code Version**: 2.1.170
+**Last Updated**: June 15, 2026
+**Claude Code Version**: 2.1.176
 **Sources**:
 - https://code.claude.com/docs/en/cli-reference
+- https://code.claude.com/docs/en/changelog#2-1-174
+- https://code.claude.com/docs/en/changelog#2-1-176
 - https://code.claude.com/docs/en/settings
 - https://code.claude.com/docs/en/changelog
 - https://code.claude.com/docs/en/troubleshooting