Skillscript

Reviewer-friendly approval UX. When a human opens a composing skill in
the dashboard to review-and-approve, the body shows
execute_skill(skill_name="get-weather") -> R and inline(skill="voice-rules")
references — but to understand "the whole picture" they previously had
to leave the page and pull up each called skill manually. v0.18.0
collapses that into an inline expansion: click the call site, see the
called skill's contract (Description + Vars + Returns) without leaving
the page.

A. SkillMeta surface completion (prerequisite)

Closes a long-standing gap: SkillMeta declared vars?: string[]
since v0.7, but FilesystemSkillStore.buildMeta() only populated
description. The dashboard composition expansion needs the full
contract (description + vars + returns) — and now everyone calling
skill_metadata MCP gets it.

• Added returns?: string[] to SkillMeta interface (matches the
  existing vars?: string[] shape)
• FilesystemSkillStore.buildMeta() now parses the source and
  populates vars + returns from parsed.vars / parsed.returns
• SqliteSkillStore.metadataRowToMeta() mirrors — source is already
  selected by skillRow(), no extra DB roundtrip
• skill_metadata MCP tool surfaces them naturally (no MCP-server
  change needed; the interface returns SkillMeta as-is)

B. Dashboard composition expansion (the headline)

New "Composes" section in the skill detail view, between Source and
Triggers. Client-side regex over the skill source finds every
execute_skill(skill_name="X") and inline(skill="X") reference,
deduplicated by (kind, name). Each ref renders collapsed as
→ execute_skill: get-weather (runtime invocation) or
→ inline: voice-rules (compile-time data inline).

Click to expand — lazy-loads the called skill's metadata via
skill_metadata MCP and renders a contract panel:

• # Description: — intent
• # Vars: — inputs (the parameter list)
• # Returns: — outputs (the return signature)
• Author badge + "Open in detail view →" drill link

For inline (data-only): also fetches the body via skill_read and
renders it under a "Inlined body (bakes at compile)" collapsible —
since the data skill's body literally lands in the host's compiled
artifact at compile time, the reviewer sees what gets baked.

Lazy-load is cached inline (re-collapsing preserves the rendered
panel; re-opening is free). Recursive — each expanded panel can
itself expand its compositions.

Implementation: vanilla JS + native <details> disclosure, no
state framework. Toggle event listener via capture-phase document
delegation since toggle doesn't bubble natively.

Tests

7 new tests in v0.18.0-skillmeta-surface.test.ts covering: description
populated, vars populated (with parser quirk note for bare names in
mixed lists), returns populated, all-three together, omitted-when-absent,
query() per-skill surface. Dashboard SPA logic verified via build +
e2e probe (visual smoke-check on the served app).

1671 tests total. Narrow-core LOC ceiling unchanged at 10500.