feat(cli): Make upgrade command channel-aware

Each install channel now queries its own source of truth for the latest
version instead of always using GitHub Releases. This prevents misleading
results when release channels drift — e.g. GitHub may publish a version
before the Homebrew tap bumps, or npm dist-tags may lag a pre-release.

- Homebrew: `brew info --json=v2` (handles exit-0-with-empty-formulae)
- npm-global / npx: `npm view <pkg>@latest version --json`
- Unknown: falls back to GitHub Releases latest endpoint

Release notes are fetched separately by tag from GitHub and are non-fatal
if unavailable (404, timeout, network error).

New DI surface: fetchLatestVersionForChannel, fetchReleaseNotesForTag,
runChannelLookupCommand (for test isolation). The dependency factory
rebuilds derived defaults from merged overrides so tests can mock at
any level.

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

Author: cameroncooke

CHANGELOG.md

@@ -4,7 +4,7 @@
 
 ### Added
 
-- Added `xcodebuildmcp upgrade` command to check for updates and upgrade in place. Supports `--check` (report-only) and `--yes`/`-y` (skip confirmation). Detects install method (Homebrew, npm-global, npx) and runs the appropriate upgrade command. Non-interactive environments exit 1 when an auto-upgrade is possible but `--yes` was not supplied.
+- Added `xcodebuildmcp upgrade` command to check for updates and upgrade in place. Supports `--check` (report-only) and `--yes`/`-y` (skip confirmation). Detects install method (Homebrew, npm-global, npx) and queries the appropriate channel source (`brew info`, `npm view`, or GitHub Releases) for the latest version. Non-interactive environments exit 1 when an auto-upgrade is possible but `--yes` was not supplied.
 
 ## [2.3.2]
 

docs/CLI.md

@@ -54,6 +54,10 @@ xcodebuildmcp upgrade --yes
 
 When both `--check` and `--yes` are supplied, `--check` wins.
 
+### Channel-aware version lookup
+
+The version check queries the source of truth for your install channel — `brew info` for Homebrew, `npm view` for npm/npx, or GitHub Releases for unknown installs. This avoids misleading results when release channels drift (e.g. GitHub may publish a version before the Homebrew tap bumps). If the channel-specific lookup fails, the command does not fall back to another source; it reports the error and exits 1.
+
 ### Install method behavior
 
 The command detects how XcodeBuildMCP was installed and adapts accordingly:
@@ -73,9 +77,9 @@ When stdin is not a TTY (CI, pipes, scripts):
 - `--yes` runs the upgrade for Homebrew and npm-global installs.
 - Without `--check` or `--yes`, the command prints the manual upgrade command and exits 1 (it cannot prompt for confirmation).
 
-### GitHub API failures
+### Lookup failures
 
-If the release check fails (network error, rate limit, timeout), the command prints the detected install method and manual upgrade instructions, then exits 1.
+If the channel-specific version check fails (network error, rate limit, timeout, missing formula), the command prints the detected install method and manual upgrade instructions, then exits 1.
 
 ## Tool Options