docs: sync to Claude Code v2.1.131 (3 patches since v2.1.126)

Sync covers v2.1.128, v2.1.129, and v2.1.131 (May 2026). Highlights:
gateway /v1/models discovery is now opt-in (CLAUDE_CODE_ENABLE_GATEWAY_MODEL_DISCOVERY),
added --plugin-url flag, disableRemoteControl setting, /mcp tool-count display,
expanded skillOverrides values, /context viz no longer leaks into conversation,
Ctrl+R cross-project default. Also reconciles slash-command count to 60+ and
fixes the skill-count entry in CATALOG.

09-advanced-features/README.md

@@ -277,7 +277,7 @@ Extended thinking is a deliberate, step-by-step reasoning process where Claude:
 
 **Automatic activation**:
 - Enabled by default for all models (Opus 4.7, Sonnet 4.6, Haiku 4.5)
-- Opus 4.7: Adaptive reasoning with effort levels: `low` (○), `medium` (◐), `high` (●), `xhigh` (Opus 4.7 only, default on Claude Code since Opus 4.7 launch, 2026-04-16), `max`. Opus 4.6 and Sonnet 4.6 also support `low`, `medium`, `high`, `max` (no `xhigh`). Opus 4.7 has a 1M-token native context window (1M context fix landed in v2.1.117 — before that, `/context` miscounted Opus 4.7 against a 200K window and triggered premature autocompact).
+- Opus 4.7: Adaptive reasoning with effort levels: `low` (○), `medium` (◐), `high` (●), `xhigh` (Opus 4.7 only, default on Claude Code since Opus 4.7 launch, 2026-04-16), `max`. Opus 4.6 and Sonnet 4.6 also support `low`, `medium`, `high`, `max` (no `xhigh`). Opus 4.7 has a 1M-token native context window (1M context fix landed in v2.1.117 — before that, `/context` miscounted Opus 4.7 against a 200K window and triggered premature autocompact). Since v2.1.129, `/context` shows its visualization in-UI only; the ASCII viz no longer leaks into the conversation context (~1.6k tokens saved per call), so `/context` is safe to invoke freely.
 - Pro/Max subscribers on Opus 4.6 / Sonnet 4.6: default effort was raised from `medium` to `high` in v2.1.117.
 - Other models: Fixed budget up to 31,999 tokens
 
@@ -1100,7 +1100,7 @@ Claude Code supports keyboard shortcuts for efficiency. Here's the complete refe
 | `Ctrl+G` | Edit plan in external editor |
 | `Ctrl+L` | Clear terminal screen |
 | `Ctrl+O` | Toggle verbose output (view reasoning) |
-| `Ctrl+R` | Reverse search history |
+| `Ctrl+R` | Reverse search history. Defaults to **all prompts across all projects** (v2.1.129+); press `Ctrl+S` inside the picker to narrow to the current project. Earlier versions defaulted to project-only. |
 | `Ctrl+T` | Toggle task list view |
 | `Ctrl+B` | Background running tasks |
 | `Esc+Esc` | Rewind code/conversation |
@@ -1370,6 +1370,8 @@ Customize the push-to-talk keybinding in your keybindings file (`/keybindings`).
 
 Channels is a Research Preview feature that pushes events from external services into a running Claude Code session via MCP servers. Sources include Telegram, Discord, iMessage, and arbitrary webhooks, allowing Claude to react to real-time notifications without polling.
 
+> **Auth (v2.1.128+)**: `--channels` now works with both Pro/Max OAuth **and** API-key (console) authentication. Earlier releases required OAuth.
+
 ### Subscribing to Channels
 
 ```bash
@@ -1539,6 +1541,18 @@ To enable:
 
 Push notifications require a Claude subscription and the Claude mobile app.
 
+### Disabling Remote Control (`disableRemoteControl`, v2.1.128+)
+
+Admins on Team or Enterprise plans can block Remote Control entirely with the `disableRemoteControl` setting. When `true`, both `claude remote-control` and `/remote-control` refuse to start.
+
+```json
+{
+  "disableRemoteControl": true
+}
+```
+
+The setting is honored at the **managed/policy** scope (e.g., `/Library/Application Support/ClaudeCode/managed-settings.json` on macOS) so it cannot be overridden by individual users. Useful when local-only execution must be enforced organization-wide.
+
 ---
 
 ## Web Sessions
@@ -2007,9 +2021,16 @@ export CLAUDE_AUTOCOMPACT_PCT_OVERRIDE=80
 export CLAUDE_STREAM_IDLE_TIMEOUT_MS=30000
 export ANTHROPIC_CUSTOM_MODEL_OPTION=my-custom-model
 export SLASH_COMMAND_TOOL_CHAR_BUDGET=50000
+
+# Output and package manager (v2.1.129+)
+export CLAUDE_CODE_FORCE_SYNC_OUTPUT=1                      # Force synchronous output for terminals where auto-detect misses (Emacs eat, etc.)
+export CLAUDE_CODE_PACKAGE_MANAGER_AUTO_UPDATE=1            # Enable background upgrades for Homebrew/WinGet installs
+export CLAUDE_CODE_ENABLE_GATEWAY_MODEL_DISCOVERY=1         # Opt in to /v1/models gateway discovery when ANTHROPIC_BASE_URL is set
 ```
 
-> **v2.1.108**: `ENABLE_PROMPT_CACHING_1H=1` — use a 1-hour prompt cache TTL instead of the default 5-minute TTL. Reduces cache misses in long, stable sessions.
+> **v2.1.108**: `ENABLE_PROMPT_CACHING_1H=1` — use a 1-hour prompt cache TTL instead of the default 5-minute TTL. Reduces cache misses in long, stable sessions. (v2.1.129 fixes a regression where the 1-hour TTL was silently downgraded to 5 minutes.)
+
+> **v2.1.129**: `CLAUDE_CODE_FORCE_SYNC_OUTPUT=1` forces synchronous output for terminals whose capability auto-detection fails (e.g., Emacs `eat`). `CLAUDE_CODE_PACKAGE_MANAGER_AUTO_UPDATE=1` enables background upgrades on Homebrew/WinGet installs, which otherwise never auto-update.
 
 ### Configuration Management Commands
 
@@ -2166,8 +2187,8 @@ For more information about Claude Code and related features:
 
 ---
 
-**Last Updated**: May 2, 2026
-**Claude Code Version**: 2.1.126
+**Last Updated**: May 6, 2026
+**Claude Code Version**: 2.1.131
 **Sources**:
 - https://code.claude.com/docs/en/permission-modes
 - https://code.claude.com/docs/en/interactive-mode