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.

09-advanced-features/README.md

@@ -1994,6 +1994,7 @@ Since v2.1.83, administrators can deploy multiple managed settings files into a
 |---------|-------------|
 | `disableBypassPermissionsMode` | Prevent users from enabling bypass permissions |
 | `availableModels` | Restrict which models users can select |
+| `enforceAvailableModels` | (v2.1.175) When `true`, the `availableModels` allowlist *also* constrains the **Default** model — if the configured default is not in the list, Claude Code falls back to the first allowed model. User and project settings can no longer widen a managed `availableModels` list. |
 | `allowedChannelPlugins` | Control which channel plugins are permitted |
 | `autoMode.environment` | Configure trusted infrastructure for auto mode |
 | `wslInheritsWindowsSettings` | Windows/WSL only (v2.1.118+): when `true`, Claude Code running inside WSL inherits managed settings from the Windows host, so enterprise policies deployed via Registry/MDM apply uniformly across the Windows and WSL shells |
@@ -2327,10 +2328,11 @@ For more information about Claude Code and related features:
 
 ---
 
-**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/troubleshooting
+- https://code.claude.com/docs/en/changelog#2-1-175
 - https://code.claude.com/docs/en/permission-modes
 - https://code.claude.com/docs/en/interactive-mode
 - https://code.claude.com/docs/en/settings