fix(doctor): use autoDetectSkillsDir so OpenClaw workspaces are reachable

[brandonlipman]

What

gbrain doctor is the only consumer of findRepoRoot() from core/repo-root.ts. Every other consumer (check-resolvable.ts:145, skillify.ts, etc.) uses autoDetectSkillsDir(), which has the full detection chain:

1. \$OPENCLAW_WORKSPACE
2. ~/.openclaw/workspace
3. findRepoRoot() walk from cwd
4. ./skills

findRepoRoot only does step 3. Result: when the user runs gbrain doctor from any directory outside the gbrain repo or the OpenClaw workspace tree (e.g., a project checkout), resolver_health reports Could not find skills directory even though the dispatcher exists at ~/.openclaw/workspace/skills/RESOLVER.md.

Repro

In any directory other than ~/gbrain or its descendants, on a system with ~/.openclaw/workspace/skills/RESOLVER.md present:

```
$ cd ~/Documents
$ gbrain doctor
[WARN] resolver_health: Could not find skills directory # before
```

But:

```
$ gbrain check-resolvable --verbose
Auto-detected skills directory from ~/.openclaw/workspace/skills: /Users/.../.openclaw/workspace/skills
```

Same machine, same setup, two different commands disagree on whether the skills dir exists. The disagreement is the bug.

Fix

Switch doctor to autoDetectSkillsDir. Brings it inline with the rest of the codebase. The detected dir is now also passed to checkSkillConformance (step 2 of the resolver_health block), which previously rebuilt the path from repoRoot — now uses the same detected path for consistency.

Test

All 15 existing tests in test/doctor.test.ts continue to pass.

```
$ bun test test/doctor.test.ts
15 pass, 0 fail, 39 expect() calls
```

---

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[garrytan]

Closing — your fix landed in master via the v0.30.3 fix-wave PR #776 (merged at ff53a4c9): "doctor uses autoDetectSkillsDir".

Thank you for the contribution — credit is preserved in the v0.30.3 CHANGELOG entry. 🙏