docs: sync to Claude Code v2.1.235 (#174)

* docs: sync to Claude Code v2.1.235

Syncs the tutorial repo from v2.1.233 to v2.1.235, fixes a fabricated
plugin-command reference and a wrong lesson-quiz answer, closes translation
fan-out gaps, and documents six new features from v2.1.234/v2.1.235.

* docs(slash-commands): scope v2.1.234 dialog-command claims to the fullscreen TUI

The v2.1.234 changelog carries two separate entries: /permissions opening
mid-turn unconditionally, and the /add-dir, /autocompact, /theme, /help,
/config and /advisor dialogs opening mid-turn in the fullscreen TUI. The
sync flattened both into one unqualified bullet, so a reader on the default
renderer would find the described behavior absent.

Also corrects the CATALOG usage-limit auto-continue row, which described an
on-by-default feature as opt-in ("Enable via /config"); the changelog says
"turn it off in /config".

* docs(advanced-features): correct spellcheck value shape, default, and scope

settings.md documents `spellcheck` as object-valued
(`{"enabled": true, "language": "en_GB"}`) and read from user settings, the
--settings flag, and managed settings only; interactive-mode.md adds that it
is off by default and needs aspell, hunspell, or ispell on PATH. CATALOG told
readers to set a bare `"spellcheck": true`, and both settings tables sit under
preambles promising project-scope settings work, which for this key they do
not.

Also repoints CATALOG's hook-configuration example at pre-tool-check.sh; the
table rename left the example on validate-bash.py, which is not in 06-hooks/.

* docs(plugins): drop the unsupported claim that /plugin update does not exist

The sync asserted "Updating is CLI-only — there is no `/plugin update` slash
command". The plugins reference contradicts that: it refers to running
`/plugin update` twice in present tense (the cache-key section, and the
explicit-version row that says `/plugin update` reports "already at the
latest version"). The v2.1.235 binary carries no `/plugin update` string and
its own update notices point at `claude plugin update <name>` in a terminal,
so the sources conflict and neither absolute is safe to teach.

Recommends the CLI form on its documented merits instead of asserting a
negative. Mirrored to vi/ja/zh/uk and to the lesson-quiz Q8 explanation,
which taught the same false negative. Q8's correct answer is unchanged.

* docs(advanced-features): complete the v2.1.234 env-var fan-out and 04 TOC (#175)

The env-var block was still headed (v2.1.221-v2.1.233) and omitted both
variables v2.1.234 added: CLAUDE_CODE_PROJECT_DIR_NAME, which had reached
only 10-cli and CATALOG, and CLAUDE_CODE_GOAL_CHECKIN_MINUTES, which was in
prose and a CATALOG row but no env-var table.

Also adds the one missing 04-subagents TOC entry: Additional Resources was
the only H2 without one, leaving the reconciled TOC at 26 of 27 sections.

10-cli/README.md

@@ -875,9 +875,10 @@ The "ultrathink" keyword in prompts activates deep reasoning. The `/effort` menu
 | `CLAUDE_CODE_DISABLE_UNKNOWN_MODEL_WINDOW_ENFORCEMENT` | Set to `1` to restore pre-v2.1.223 auto-compact behavior on unrecognized model IDs (v2.1.223) |
 | `CLAUDE_CODE_WORKFLOW_PREFIX_STAGGER_MS` | Set to `0` to disable prefix staggering on dynamic-workflow fan-out (v2.1.229) |
 | `CLAUDE_CODE_USER_DIALOG_TIMEOUT_MS` | Overrides the `dialogExpiry` setting (v2.1.224) |
+| `CLAUDE_CODE_PROJECT_DIR_NAME` | Overrides the per-project transcript directory name Claude Code derives from the project path (v2.1.234) |
 
-> **These seven rows are changelog-sourced.** The CLI reference page has no dedicated
-> environment-variable section, so they are documented from the v2.1.221–v2.1.233
+> **These eight rows are changelog-sourced.** The CLI reference page has no dedicated
+> environment-variable section, so they are documented from the v2.1.221–v2.1.234
 > changelog entries rather than a reference page.
 
 > **`CLAUDE_CODE_DISABLE_1M_CONTEXT` widened in v2.1.223**: it now holds **every** Claude model with a native 1M-token window to 200K via auto-compaction, not just a fixed list of model IDs.
@@ -899,6 +900,7 @@ These keys live in a `settings.json` file (`~/.claude/settings.json` for user sc
 | `sandbox.filesystem.disabled` | (v2.1.216) Skips filesystem sandboxing while keeping network egress control enforced. For workflows where file sandboxing breaks tooling but network policy must stay enforced. |
 | `emojiCompletionEnabled` | (v2.1.217) Enables emoji shortcode autocomplete in the prompt input (e.g. typing `:heart:` inserts ❤️). Set `false` to disable. |
 | `workflowSizeGuideline` | (v2.1.219) Sets the advisory Dynamic workflow size guideline from any settings file. The guideline is guidance Claude aims for, not a hard cap — the default is medium (aim for fewer than 15 agents), and other sizes or unrestricted can be selected. While this key is set, the "Dynamic workflow size" row is hidden in `/config`. Distinct from `CLAUDE_CODE_MAX_CONCURRENT_SUBAGENTS`, which is an enforced concurrency limit. |
+| `spellcheck` | (v2.1.235) Underlines misspelled words in the prompt input using whichever of `aspell`, `hunspell`, or `ispell` is on your `PATH`, tried in that order. Object-valued — `{"enabled": true, "language": "en_GB"}` — and off by default. **Read from user settings, the `--settings` flag, and managed settings only**: a `spellcheck` block in a project `.claude/settings.json` or `.claude/settings.local.json` is ignored. See also [Advanced Features → Additional Per-User Settings](../09-advanced-features/README.md#additional-per-user-settings). |
 
 ```json
 {
@@ -1012,8 +1014,8 @@ claude -p --output-format json "query"
 
 ---
 
-**Last Updated**: August 15, 2026
-**Claude Code Version**: 2.1.233
+**Last Updated**: August 19, 2026
+**Claude Code Version**: 2.1.235
 **Sources**:
 - https://code.claude.com/docs/en/cli-reference
 - https://code.claude.com/docs/en/env-vars
@@ -1035,4 +1037,6 @@ claude -p --output-format json "query"
 - https://code.claude.com/docs/en/overview
 - https://code.claude.com/docs/en/sub-agents
 - https://code.claude.com/docs/en/headless
+- https://code.claude.com/docs/en/cli-reference.md
+- https://code.claude.com/docs/en/settings.md
 **Compatible Models**: Claude Fable 5, Claude Opus 5, Claude Sonnet 5, Claude Sonnet 4.6, Claude Opus 4.8, Claude Haiku 4.5