docs: update Claude Code releases (v2.1.19, v2.1.18)

- v2.1.19: CLAUDE_CODE_ENABLE_TASKS env var, $0/$1 argument shorthand
- v2.1.18: Customizable keyboard shortcuts with /keybindings
- Breaking: $ARGUMENTS.0 → $ARGUMENTS[0] syntax change (v2.1.19)
- Milestone: Keyboard shortcuts added to feature list
- Update both YAML and Markdown files
- Sync dates to 2026-01-25

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

guide/claude-code-releases.md

@@ -4,13 +4,13 @@
 > **Full details**: [github.com/anthropics/claude-code/CHANGELOG.md](https://github.com/anthropics/claude-code/blob/main/CHANGELOG.md)
 > **Machine-readable**: [claude-code-releases.yaml](../machine-readable/claude-code-releases.yaml)
 
-**Latest**: v2.1.17 | **Updated**: 2026-01-23
+**Latest**: v2.1.19 | **Updated**: 2026-01-25
 
 ---
 
 ## Quick Jump
 
-- [2.1.x Series (January 2026)](#21x-series-january-2026) — Task management, Skill hot-reload, Vim motions
+- [2.1.x Series (January 2026)](#21x-series-january-2026) — Task management, Keyboard shortcuts, Skill hot-reload
 - [2.0.x Series (Nov 2025 - Jan 2026)](#20x-series-november-2025---january-2026) — Opus 4.5, Claude in Chrome, Background agents
 - [Breaking Changes Summary](#breaking-changes-summary)
 - [Milestone Features](#milestone-features)
@@ -19,6 +19,31 @@
 
 ## 2.1.x Series (January 2026)
 
+### v2.1.19 (2026-01-25)
+
+- **New**: `CLAUDE_CODE_ENABLE_TASKS` environment variable — Set to `false` to temporarily revert to old task system
+- **New**: Argument shorthand in custom commands — Use `$0`, `$1`, etc. instead of verbose syntax
+- [VSCode] Session forking and rewind functionality enabled for all users
+- Fixed: Crashes on processors without AVX instruction support
+- Fixed: Dangling Claude Code processes when terminal closed (SIGKILL fallback)
+- Fixed: `/rename` and `/tag` not updating correct session when resuming from different directory (git worktrees)
+- Fixed: Resuming sessions by custom title from different directory
+- Fixed: Pasted text lost when using prompt stash (Ctrl+S) and restore
+- Fixed: Agent list displaying "Sonnet (default)" instead of "Inherit (default)" for agents without explicit model
+- Fixed: Backgrounded hook commands blocking session instead of returning early
+- Fixed: File write preview omitting empty lines
+- Changed: Skills without additional permissions/hooks allowed without approval
+- [SDK] Added replay of queued_command attachment messages when `replayUserMessages` enabled
+
+**⚠️ Breaking**:
+- Indexed argument syntax changed: `$ARGUMENTS.0` → `$ARGUMENTS[0]` (bracket syntax)
+
+### v2.1.18 (2026-01-24) ⭐
+
+- ⭐ **Customizable keyboard shortcuts** — Configure keybindings per context, create chord sequences, personalize workflow
+- Run `/keybindings` to get started
+- Learn more: [code.claude.com/docs/en/keybindings](https://code.claude.com/docs/en/keybindings)
+
 ### v2.1.17 (2026-01-23)
 
 - Fix: Crashes on processors without AVX instruction support
@@ -257,12 +282,19 @@
 | v2.1.6 | Shell line continuation permission bypass |
 | v2.1.7 | Wildcard permission rules compound commands |
 
+### Syntax
+
+| Version | Change |
+|---------|--------|
+| v2.1.19 | Indexed argument syntax changed: `$ARGUMENTS.0` → `$ARGUMENTS[0]` (bracket syntax) |
+
 ---
 
 ## Milestone Features
 
 | Version | Key Features |
 |---------|--------------|
+| **v2.1.18** | Customizable keyboard shortcuts with /keybindings |
 | **v2.1.16** | New task management system with dependency tracking |
 | **v2.1.0** | Skill hot-reload, Shift+Enter OOTB, Vim motions, /plan command |
 | **v2.0.74** | LSP tool for code intelligence |
@@ -286,4 +318,4 @@
 
 ---
 
-*Last updated: 2026-01-23 | [Back to main guide](./ultimate-guide.md)*
+*Last updated: 2026-01-25 | [Back to main guide](./ultimate-guide.md)*

machine-readable/claude-code-releases.yaml

@@ -3,8 +3,8 @@
 # Purpose: Track Claude Code product releases for documentation sync
 # Maintained: Manual updates when new releases are announced
 
-latest: "2.1.17"
-updated: "2026-01-23"
+latest: "2.1.19"
+updated: "2026-01-25"
 
 # ════════════════════════════════════════════════════════════════
 # RELEASES (newest first, condensed highlights only)
@@ -15,6 +15,23 @@ releases:
   # 2.1.x Series (January 2026)
   # ─────────────────────────────────────────────────────────────
 
+  - version: "2.1.19"
+    date: "2026-01-25"
+    highlights:
+      - "New: CLAUDE_CODE_ENABLE_TASKS env var (set false for old task system)"
+      - "New: Shorthand $0, $1 for arguments in custom commands"
+      - "[VSCode] Session forking and rewind enabled for all users"
+      - "Fixed: Multiple session resuming/naming issues with git worktrees"
+    breaking:
+      - "Indexed argument syntax changed: $ARGUMENTS.0 → $ARGUMENTS[0] (bracket syntax)"
+
+  - version: "2.1.18"
+    date: "2026-01-24"
+    highlights:
+      - "⭐ Customizable keyboard shortcuts with /keybindings command"
+      - "Per-context keybindings, chord sequences, workflow personalization"
+    breaking: []
+
   - version: "2.1.17"
     date: "2026-01-23"
     highlights:
@@ -402,11 +419,14 @@ breaking_summary:
     - "npm installations deprecated - use native installer (v2.1.15)"
   behavior:
     - "ultrathink/think keywords now cosmetic only — thinking default with Opus 4.5 (v2.0.67)"
+  syntax:
+    - "Indexed argument syntax changed: $ARGUMENTS.0 → $ARGUMENTS[0] (v2.1.19)"
 
 # ════════════════════════════════════════════════════════════════
 # MILESTONE FEATURES (quick reference)
 # ════════════════════════════════════════════════════════════════
 milestones:
+  "2.1.18": "Customizable keyboard shortcuts with /keybindings"
   "2.1.16": "New task management system with dependency tracking"
   "2.1.0": "Skill hot-reload, Shift+Enter OOTB, Vim motions, /plan command"
   "2.0.74": "LSP tool for code intelligence"