feat(plugin): auto-install statusLine, tmux sidebar, and config update

- Add _install_statusline() to auto-copy codingbuddy-hud.py and register
  in settings.json, replacing OMC while preserving custom statusLines
- Add _setup_tmux_sidebar() with $TMUX detection, duplicate pane prevention,
  and i18n suggestion messages (en/ko) for non-tmux users
- Add _get_plugin_version() to read version from plugin.json dynamically
- Set CODINGBUDDY_AUTO_TUI=0 to disable standalone TUI auto-launch
- Wire Steps 2.5, 4.5, 6.5 into session-start main() flow
- Add 15 tests (9 install + 6 tmux), all passing

Closes #1089
Closes #1091
Closes #1092

Author: JeremyDev87

docs/plans/2026-03-28-wave3-auto-install-tmux-sidebar.md

@@ -0,0 +1,216 @@
+# Wave 3: Auto-Install StatusLine + tmux Sidebar + Config Change
+
+> **For Claude:** REQUIRED SUB-SKILL: Use superpowers:executing-plans to implement this plan task-by-task.
+
+**Goal:** Wire up statusLine auto-installation in session-start, add tmux sidebar auto-setup, and set `CODINGBUDDY_AUTO_TUI=0`. All changes are in `session-start.py`.
+
+**Architecture:** Three new functions added to `session-start.py`, inserted as Step 2.5, Step 4.5, and Step 6.5 in the existing `main()` flow.
+
+**Tech Stack:** Python 3, shutil, subprocess, json
+
+**Issues:** #1089, #1091, #1092
+
+## Alternatives
+
+### Decision: HUD script source discovery
+
+| Criteria | Reuse find_plugin_source() with param | Separate find function |
+|---|---|---|
+| DRY | Reuses existing 3-tier search | Duplicates logic |
+| Flexibility | Need to parameterize filename | Hardcoded to one file |
+| Risk | Changing shared function may break hook install | Isolated |
+
+**Decision:** Separate helper `_find_hud_source()` that follows the same 3-tier pattern but searches for `codingbuddy-hud.py`. Simpler and zero risk to existing hook installation.
+
+---
+
+## Part A: #1089 — Auto-Install StatusLine
+
+### Step A1: Write test — `_install_statusline`
+
+**File:** `packages/claude-code-plugin/tests/test_session_start_hud.py`
+
+Tests:
+- `test_installs_hud_script_to_claude_hud_dir` — copies file, sets permissions
+- `test_sets_statusline_in_settings` — writes statusLine config
+- `test_replaces_omc_statusline` — replaces omc-hud with codingbuddy-hud
+- `test_skips_custom_statusline` — preserves non-OMC custom statusLine
+- `test_skips_if_already_installed` — no-op when codingbuddy-hud already set
+- `test_sets_auto_tui_to_zero` — changes CODINGBUDDY_AUTO_TUI from 1 to 0
+
+### Step A2: Implement `_find_hud_source()`
+
+Same 3-tier search as `find_plugin_source()` but for `codingbuddy-hud.py`:
+1. `CLAUDE_PLUGIN_DIR` env → `hooks/codingbuddy-hud.py`
+2. Plugin cache paths → `hooks/codingbuddy-hud.py`
+3. Dev paths → `hooks/codingbuddy-hud.py`
+
+### Step A3: Implement `_install_statusline(home, settings_file)`
+
+```python
+def _install_statusline(home: Path, settings_file: Path) -> None:
+    """Install codingbuddy statusLine and set CODINGBUDDY_AUTO_TUI=0."""
+    # 1. Find source
+    source = _find_hud_source()
+    if not source:
+        return
+
+    # 2. Copy to ~/.claude/hud/
+    hud_dir = home / ".claude" / "hud"
+    hud_dir.mkdir(parents=True, exist_ok=True)
+    target = hud_dir / "codingbuddy-hud.py"
+    shutil.copy(source, target)
+    target.chmod(0o755)
+
+    # 3. Update settings.json
+    settings = _read_settings_file(settings_file) if settings_file.exists() else {}
+
+    # Check existing statusLine
+    current_sl = settings.get("statusLine", {}).get("command", "")
+    if "codingbuddy-hud" in current_sl:
+        pass  # already installed
+    elif "omc-hud" in current_sl or not current_sl:
+        settings["statusLine"] = {
+            "type": "command",
+            "command": f'python3 "{home}/.claude/hud/codingbuddy-hud.py"'
+        }
+    # else: custom statusLine, preserve
+
+    # 4. Set CODINGBUDDY_AUTO_TUI=0 (#1092)
+    env = settings.setdefault("env", {})
+    if env.get("CODINGBUDDY_AUTO_TUI") == "1":
+        env["CODINGBUDDY_AUTO_TUI"] = "0"
+
+    _write_settings_file(settings_file, settings)
+```
+
+### Step A4: Wire into `main()` as Step 2.5
+
+After line 492 (after status message), before Step 3:
+```python
+        # Step 2.5: Install codingbuddy statusLine (#1089, #1092)
+        try:
+            _install_statusline(home, settings_file)
+        except Exception:
+            pass
+```
+
+### Step A5: Implement Step 4.5 — Init HUD state
+
+After line 525 (after stats init):
+```python
+        # Step 4.5: Initialize HUD state (#1089)
+        try:
+            _ensure_lib_path()
+            from hud_state import init_hud_state
+            from session_utils import get_session_id as _get_sid_hud
+            init_hud_state(_get_sid_hud(), "5.1.1")
+        except Exception:
+            pass
+```
+
+---
+
+## Part B: #1091 — tmux Sidebar Auto-Setup
+
+### Step B1: Write test — tmux detection + sidebar
+
+**File:** `packages/claude-code-plugin/tests/test_tmux_sidebar.py`
+
+Tests:
+- `test_detects_tmux_env` — returns True when $TMUX set
+- `test_no_tmux_env` — returns False when $TMUX unset
+- `test_sidebar_pane_exists_detection` — detects existing codingbuddy pane
+- `test_prints_tmux_suggestion_when_not_in_tmux` — outputs tip message
+
+### Step B2: Implement `_setup_tmux_sidebar()`
+
+```python
+import subprocess
+
+TMUX_SUGGESTION = {
+    "en": (
+        "╭───────────────────────────────────────────────╮\n"
+        "│ ◕‿◕ Tip: Run Claude Code inside tmux for     │\n"
+        "│     the full CodingBuddy sidebar experience!  │\n"
+        "│                                               │\n"
+        "│     tmux new -s dev                           │\n"
+        "│     claude                                    │\n"
+        "╰───────────────────────────────────────────────╯"
+    ),
+    "ko": (
+        "╭───────────────────────────────────────────────╮\n"
+        "│ ◕‿◕ Tip: tmux 안에서 Claude Code를 실행하면  │\n"
+        "│     CodingBuddy 사이드바를 볼 수 있어요!      │\n"
+        "│                                               │\n"
+        "│     tmux new -s dev                           │\n"
+        "│     claude                                    │\n"
+        "╰───────────────────────────────────────────────╯"
+    ),
+}
+
+def _sidebar_pane_exists() -> bool:
+    try:
+        result = subprocess.run(
+            ["tmux", "list-panes", "-F", "#{pane_current_command}"],
+            capture_output=True, text=True, timeout=2,
+        )
+        return "codingbuddy" in result.stdout
+    except Exception:
+        return False
+
+def _setup_tmux_sidebar() -> None:
+    if not os.environ.get("TMUX"):
+        # Print suggestion
+        lang = _get_cached_language()
+        tip = TMUX_SUGGESTION.get(lang, TMUX_SUGGESTION["en"])
+        print(tip, file=sys.stderr)
+        return
+
+    if _sidebar_pane_exists():
+        return
+
+    subprocess.Popen(
+        ["tmux", "split-window", "-h", "-l", "25%", "-d", "codingbuddy", "tui"],
+        stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL,
+    )
+    subprocess.Popen(
+        ["tmux", "select-pane", "-L"],
+        stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL,
+    )
+```
+
+### Step B3: Wire into `main()` as Step 6.5
+
+After buddy greeting (end of Step 6):
+```python
+        # Step 6.5: tmux sidebar auto-setup (#1091)
+        try:
+            _setup_tmux_sidebar()
+        except Exception:
+            pass
+```
+
+---
+
+## Execution Order
+
+1. Write tests (A1 + B1)
+2. Implement functions (A2-A5 + B2-B3)
+3. Run all tests
+4. Commit + ship
+
+## Files Modified
+
+| File | Changes |
+|------|---------|
+| `hooks/session-start.py` | Add `_find_hud_source`, `_install_statusline`, `_setup_tmux_sidebar`, `_sidebar_pane_exists`, `TMUX_SUGGESTION` + wire Steps 2.5, 4.5, 6.5 |
+| `tests/test_session_start_hud.py` | NEW — statusLine install tests |
+| `tests/test_tmux_sidebar.py` | NEW — tmux detection tests |
+
+## Verification
+
+1. `python3 -m pytest tests/test_session_start_hud.py tests/test_tmux_sidebar.py -v`
+2. `python3 -m pytest tests/ -q` (full regression)
+3. Manual: Start new Claude Code session → check `~/.claude/settings.json` statusLine
+4. Manual (tmux): Start Claude Code in tmux → verify sidebar pane appears