feat(channels): support WhatsApp-only mode (Telegram becomes optional)

Until now Telegram was a hard requirement. The bot would refuse to start
without TELEGRAM_BOT_TOKEN and TELEGRAM_ALLOWED_USER_ID, even when the
user only wanted to use WhatsApp. This commit lifts that constraint so
each instance can pick: Telegram only, Telegram + WhatsApp, or
WhatsApp only.

Config (src/config.ts)
- Adds telegram.enabled = (token present AND user_id valid).
- Telegram env vars are now optional. Whatever is missing simply turns
  the channel off.
- Cross-channel invariant: at least one of telegram.enabled /
  whatsapp.enabled must be true; otherwise loadConfig() throws with a
  clear hint to run setup.sh.

Validation (src/runtime/bootstrap.ts)
- validateRuntimeEnvValues now accepts WhatsApp-only configs.
- Catches half-configured Telegram (token without user_id) so users
  don't silently fall through to WhatsApp-only because of a typo.
- New tests cover: WhatsApp-only valid, both channels valid, no channel
  invalid, partial Telegram invalid.

Bootstrap (src/app/start-bot-app.ts)
- Telegram bot creation, scheduled-task runtime init, webhook check and
  bot.start() are all guarded by config.telegram.enabled.
- WhatsApp-only mode replaces grammy's blocking long-poll with a
  Promise resolved by the shutdown handler — Baileys runs in the
  background and the process stays alive on signals.

Setup (setup.sh)
- New STEP 2/12 — Messaging Channels — asks Telegram only / both /
  WhatsApp only at the start of the wizard.
- STEP 3 (Telegram token) and STEP 4 (User ID) are skipped with a
  visible "(skipped)" line when the user picked WhatsApp only.
- STEP 8 (WhatsApp number) is skipped when WhatsApp is off.
- Generated .env still writes empty Telegram lines so the user sees
  what the alternative is and can flip it later.
- Summary block reflects each channel's enabled/disabled state.

CLI (bin/opencode-assistant)
- --doctor stops requiring TELEGRAM_BOT_TOKEN. It now reports each
  channel's status independently, and only fails if neither is
  configured.
- WhatsApp QR hint switched from `--logs bot` to the `--qr` shortcut.

Scheduled tasks (src/scheduled-task/runtime.ts)
- No code change: the runtime already gates registerTask() on
  initialized; in WhatsApp-only mode start-bot-app.ts simply skips
  initialize() and logs that /task is unavailable in this mode.

Docs
- docs/WHATSAPP_SETUP.md: documents the three modes, the WhatsApp-only
  caveats (no /task, no permission/question UI), and the multi-channel
  .env layout.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: JohanYP

bin/opencode-assistant

@@ -587,30 +587,37 @@ cmd_doctor() {
   check "Docker installed" command -v docker
   check "Docker daemon responding" docker info
 
-  # .env
+  # .env — at least one channel must be configured (Telegram or WhatsApp).
+  # Each channel is checked independently; doctor reports which are active.
   if [[ -f "$REPO_DIR/.env" ]]; then
-    if grep -qE '^TELEGRAM_BOT_TOKEN=.+' "$REPO_DIR/.env"; then
-      ok ".env present with TELEGRAM_BOT_TOKEN"
-    else
-      err ".env exists but TELEGRAM_BOT_TOKEN is empty — run ./setup.sh"
-      fails=$((fails + 1))
+    local has_telegram=false has_whatsapp=false
+
+    if grep -qE '^TELEGRAM_BOT_TOKEN=.+' "$REPO_DIR/.env" \
+       && grep -qE '^TELEGRAM_ALLOWED_USER_ID=[1-9][0-9]*' "$REPO_DIR/.env"; then
+      ok "Telegram channel configured"
+      has_telegram=true
     fi
 
-    # WhatsApp (only validated when the user opted in)
     if grep -qE '^WHATSAPP_ENABLED=true' "$REPO_DIR/.env"; then
       if grep -qE '^WHATSAPP_ALLOWED_NUMBER=[0-9]{8,}' "$REPO_DIR/.env"; then
-        ok "WhatsApp enabled with allowed number"
+        ok "WhatsApp channel configured"
+        has_whatsapp=true
         # If the auth dir is empty AND the bot is up, the user hasn't paired yet.
         if [[ "$(container_state bot)" == "running" ]] \
            && dc exec -T bot test -d /app/data/whatsapp-auth >/dev/null 2>&1 \
            && [[ -z "$(dc exec -T bot ls /app/data/whatsapp-auth 2>/dev/null | tr -d '\r')" ]]; then
-          warn "WhatsApp auth dir is empty — scan the QR with: opencode-assistant --logs bot"
+          warn "WhatsApp auth dir is empty — scan the QR with: opencode-assistant --qr"
         fi
       else
         err "WHATSAPP_ENABLED=true but WHATSAPP_ALLOWED_NUMBER missing or invalid"
         fails=$((fails + 1))
       fi
     fi
+
+    if ! $has_telegram && ! $has_whatsapp; then
+      err "No messaging channel configured — run ./setup.sh (Telegram and/or WhatsApp required)"
+      fails=$((fails + 1))
+    fi
   else
     err ".env not found — run ./setup.sh"
     fails=$((fails + 1))

docs/WHATSAPP_SETUP.md

@@ -1,6 +1,16 @@
-# WhatsApp setup (optional second channel)
+# WhatsApp setup
 
-The bot can connect to WhatsApp as a second channel alongside Telegram, using a **separate dedicated phone number**. Opt-in, disabled by default.
+Opencode-Assistant can run with WhatsApp as a **second channel alongside Telegram** or as the **only channel** (no Telegram). Both modes use [Baileys](https://github.com/WhiskeySockets/Baileys), an unofficial WhatsApp Web client, and require a **dedicated phone number** — see the warnings below.
+
+## Available modes
+
+| Mode | When to choose it |
+|---|---|
+| **Telegram only** (default) | Best UX: inline pickers, pinned status, `/skills`, `/projects`, `/task`, etc. all work |
+| **Telegram + WhatsApp** | Talk to the bot from either app; reminders fire on both. Telegram remains where permission/question dialogs appear |
+| **WhatsApp only** | No Telegram account needed. More limited UX (see below) |
+
+The wizard's `STEP 2/12 — Messaging Channels` asks which mode you want before collecting the relevant credentials.
 
 ## What works in V1
 
@@ -13,14 +23,22 @@ The bot can connect to WhatsApp as a second channel alongside Telegram, using a
 - ✅ Numbered-menu reply for `/sessions` (reply with `1`, `2`, ...)
 - ✅ Reminders and weekly memory backup notifications fire on **both** channels (Telegram + WhatsApp), driven by a multi-target registry in `cron/reminder.ts`
 
-## Known V1 limitations
+## Known V1 limitations (apply to all modes)
 
-- ⚠️ **Permission and question dialogs still live in Telegram.** When a prompt sent from WhatsApp triggers a permission request (bash, edit, webfetch...) or a question, the dialog appears in Telegram. Approve there and the WhatsApp prompt completes. If you don't have a Telegram device handy, the prompt will block until it times out. Mirroring these dialogs to WhatsApp as numbered menus is on the V1.x roadmap (requires SSE fanout + dual state managers).
 - ⚠️ **No streaming responses** — WhatsApp users see the final reply only, not intermediate tool-call updates. The bot uses `session.prompt` (sync) instead of `promptAsync` + SSE.
 - ⚠️ **Audio output is plain MP3, not push-to-talk** (no waveform UI). PTT requires OPUS encoding which would need ffmpeg in the container; deferred to V1.x.
-- ⚠️ **No model/agent/variant pickers, no `/skills`, no `/projects`, no `/task`** from WhatsApp. Use Telegram for those.
+- ⚠️ **No model/agent/variant pickers, no `/skills`, no `/projects`, no `/task`** from WhatsApp. Use Telegram for those when running in mixed mode.
 - ⚠️ **Concurrent prompts on the same session are rejected** with a "previous task is still running" hint.
 
+## WhatsApp-only mode — extra limitations
+
+When you choose "WhatsApp only" in the wizard, **no Telegram bot is started**. That means:
+
+- ❌ **Scheduled tasks (`/task`) are unavailable.** They require Telegram-rendered output (inline keyboards for continue/cancel buttons). Reminders that don't run an OpenCode session still work via the cron registry.
+- ❌ **Permission and question dialogs from OpenCode have no UI surface.** A prompt that triggers `bash`/`edit`/`webfetch` permission will hang. Either skip prompts that need permissions, or run in mixed mode and approve from Telegram.
+
+In **mixed mode** (Telegram + WhatsApp), permission/question dialogs still appear in Telegram even when the prompt was sent from WhatsApp. Approve there and the WhatsApp prompt completes. Mirroring those dialogs to WhatsApp as numbered menus is on the V1.x roadmap.
+
 ## Requirements
 
 - A **dedicated WhatsApp account** (a phone number that will be the bot). Don't link your main personal account — Meta may ban numbers that talk to unofficial clients like Baileys.
@@ -31,13 +49,20 @@ The bot can connect to WhatsApp as a second channel alongside Telegram, using a
 In `.env`:
 
 ```bash
+# Telegram (leave empty for WhatsApp-only mode)
+TELEGRAM_BOT_TOKEN=
+TELEGRAM_ALLOWED_USER_ID=
+
+# WhatsApp
 WHATSAPP_ENABLED=true
 WHATSAPP_ALLOWED_NUMBER=34666999999    # country code + number, no +
 # WHATSAPP_AUTH_DIR=./data/whatsapp-auth   # default; rarely overridden
 ```
 
 `WHATSAPP_ALLOWED_NUMBER` accepts either bare digits (`34666999999`) or full Baileys JID (`34666999999@s.whatsapp.net`). The bot normalizes both.
 
+**At least one channel must be configured** — empty Telegram fields + `WHATSAPP_ENABLED=false` is rejected at startup.
+
 ## First start
 
 ```bash