ProjectStateFileCheck.fix() is unreachable — its message tells users to run a fix that never runs

[bguidolim]

Summary

ProjectStateFileCheck has a complete, working fix() that rebuilds .mcs-project by inferring packs from CLAUDE.local.md section markers. It is dead code: the check returns .warn in both branches where that fix applies, and DoctorRunner.runChecks appends to pendingFixes only from the case .fail arm. A .warn never reaches executePendingFixes, so the fix is never invoked.

Both warning messages tell the user to do exactly the thing that will not happen:

• "corrupt .mcs-project: … — run 'mcs doctor --fix'"
• "CLAUDE.local.md exists but .mcs-project missing — run 'mcs doctor --fix'"

Symptom

mcs doctor reports a corrupt or missing .mcs-project, instructs the user to run mcs doctor --fix, and --fix does nothing about it. The recovery has to be done by hand (delete the file and re-run mcs sync) despite the automated path existing.

Two gates, both need fixing

Returning .fail alone is not sufficient. executePendingFixes then partitions on fixCommandPreview, and ProjectStateFileCheck does not override it, so it would land in the "unfixable" bucket where only .notFixable is surfaced — its .fixed result would be dropped without incrementing fixedCount. That is the same failure mode as PR #162.

So:

• return .fail instead of .warn in the two recoverable branches (leave the .skip branch alone — no state and no CLAUDE.local.md is a legitimate un-synced project, not a fault)
• add a fixCommandPreview describing the rebuild, e.g. "rebuild .mcs-project from CLAUDE.local.md section markers"

Severity note: DoctorCommand.perform() discards the DoctorSummary and sets no exit code, so promoting these to .fail only moves them into the "Issues" tally — it does not change any command's exit status.

Acceptance criteria

• mcs doctor --fix in a project with CLAUDE.local.md and no .mcs-project rebuilds the state file
• The same for a corrupt .mcs-project
• The applied fix is reported and counted in the summary
• A project with neither file still reports .skip, not a failure