feat: add skills settings and gateway skills management

docs/mac/skills.md

@@ -0,0 +1,24 @@
+---
+summary: "macOS Skills settings UI and gateway-backed status"
+read_when:
+  - Updating the macOS Skills settings UI
+  - Changing skills gating or install behavior
+---
+# Skills (macOS)
+
+The macOS app surfaces Clawdis skills via the gateway; it does not parse skills locally.
+
+## Data source
+- `skills.status` (gateway) returns all skills plus eligibility and missing requirements.
+- Requirements are derived from `metadata.clawdis.requires` in each `SKILL.md`.
+
+## Install actions
+- `metadata.clawdis.install` defines install options (brew/node/go/pnpm/git/shell).
+- The app calls `skills.install` to run installers on the gateway host.
+
+## Env/API keys
+- The app stores keys in `~/.clawdis/clawdis.json` under `skills.<skillKey>`.
+- `skills.update` patches `enabled`, `apiKey`, and `env`.
+
+## Remote mode
+- Install + config updates happen on the gateway host (not the local Mac).