feat: add dev update channel

docs/cli/update.md

@@ -16,6 +16,7 @@ If you installed via **npm/pnpm** (global install, no git metadata), use the pac
 ```bash
 clawdbot update
 clawdbot update --channel beta
+clawdbot update --channel dev
 clawdbot update --tag beta
 clawdbot update --restart
 clawdbot update --json
@@ -25,7 +26,7 @@ clawdbot --update
 ## Options
 
 - `--restart`: restart the Gateway daemon after a successful update.
-- `--channel <stable|beta>`: set the update channel for npm installs (persisted in config).
+- `--channel <stable|beta|dev>`: set the update channel (git + npm; persisted in config).
 - `--tag <dist-tag|version>`: override the npm dist-tag or version for this update only.
 - `--json`: print machine-readable `UpdateRunResult` JSON.
 - `--timeout <seconds>`: per-step timeout (default is 1200s).
@@ -34,13 +35,20 @@ Note: downgrades require confirmation because older versions can break configura
 
 ## What it does (git checkout)
 
+Channels:
+
+- `stable`: checkout the latest non-beta tag, then build + doctor.
+- `beta`: checkout the latest `-beta` tag, then build + doctor.
+- `dev`: checkout `main`, then fetch + rebase.
+
 High-level:
 
 1. Requires a clean worktree (no uncommitted changes).
-2. Fetches and rebases against `@{upstream}`.
-3. Installs deps (pnpm preferred; npm fallback).
-4. Builds + builds the Control UI.
-5. Runs `clawdbot doctor` as the final “safe update” check.
+2. Switches to the selected channel (tag or branch).
+3. Fetches and rebases against `@{upstream}` (dev only).
+4. Installs deps (pnpm preferred; npm fallback).
+5. Builds + builds the Control UI.
+6. Runs `clawdbot doctor` as the final “safe update” check.
 
 ## `--update` shorthand
 
@@ -49,5 +57,6 @@ High-level:
 ## See also
 
 - `clawdbot doctor` (offers to run update first on git checkouts)
+- [Development channels](/install/development-channels)
 - [Updating](/install/updating)
 - [CLI reference](/cli)