[Feature]: Add --json output to preset info and extension info with fully-expanded per-contribution detail (per-pack detail view; complements list --json summary counts)

从 preset info --json 和 extension info --json CLI 入口开始，然后跟踪 composition/collect.mjs::parseProvidesEntries 和 ::parseHookDeclarations 中现有的规范化过程；查看 extensions/__init__.py:622-626 以了解仅替换行为。将输出与配套的 list --json 和 artifact info --json 契约进行比较。指定的扩展 schema、稳定 ID、规范化、错误、测试和 CLI 参考文档全部完成后，即视为完成。

Problem Statement

Today specify preset info <id> and specify extension info <id> emit only text. speckit-wizard-canvas reads the raw preset.yml / extension.yml files with js-yaml and re-normalizes the shape itself in composition/collect.mjs::parseProvidesEntries and ::parseHookDeclarations — including strategy inference from shorthand keys (replaces vs. wraps vs. prepends vs. appends), hook-phase normalization (phase vs. trigger, command vs. targetCommand), and script-runtime inference by globbing scripts/{bash,powershell,python}/*.{sh,ps1,py}. All of this is server-side data being reconstructed on the client.

Downstream consumers need the structured shape returned by the CLI itself so they can stop reconstructing it.

How this differs from the companion preset list --json / extension list --json issue. The list variant operates on the collection of installed packs and returns a JSON array, one row per pack, where provides is just integer counts ({ commands: 4, templates: 2, scripts: 1, hooks: 3 }) — a summary/catalog view suitable for "here's every preset the project has". info operates on one pack, addressed by id, and returns a single JSON object where provides is fully expanded — every command, template, script, and hook enumerated with its full per-contribution schema (id, name, description, artifact, optional, handoffs, strategy, sourcePath, runtimes, etc.). A wizard rendering "here's what speckit.git contributes to my project" needs the info detail; list's counts are not enough. Both surfaces are required; neither is a subset of the other.

Proposed Solution

Add --json to both info commands. Output shape:

{
  "id": "…", "name": "…", "description": "…", "version": "…",
  "author": "…", "priority": 100, "enabled": true, "source": { "…": "…" },
  "commands": [
    { "id": "…", "name": "speckit.plan", "description": "…",
      "artifact": "specs/{feature}/plan.md", "optional": false,
      "handoffs": [ { "to": "speckit.tasks", "when": "…", "message": "…" } ],
      "strategy": "wrap",
      "source": { "layer": "preset", "presetId": "…" },
      "sourcePath": "commands/speckit.plan.md" }
  ],
  "templates": [
    { "id": "…", "name": "…", "description": "…",
      "strategy": "replace",
      "source": { "…": "…" }, "sourcePath": "templates/…" }
  ],
  "scripts": [
    { "id": "…", "name": "…", "description": "…",
      "strategy": "replace",
      "source": { "…": "…" }, "sourcePath": "scripts/bash/…",
      "runtimes": ["bash", "powershell", "python"] }
  ],
  "hooks": [
    { "id": "…", "name": "…", "description": "…",
      "trigger": "before_speckit.plan", "targetCommand": "speckit.git.checklist",
      "sourcePath": "commands/speckit.git.checklist.md",
      "optional": false, "priority": 10 }
  ]
}

Notes:

• Preset objects omit hooks.
• Extension commands/templates/scripts entries omit strategy (they are always replace, per the replace-only rule enforced at extensions/__init__.py:622-626).
• id values use the stable-id scheme from the companion "stable id / lookupId" issue; the id on a per-contribution entry is what the companion specify artifact info --json stack's lookupId points at.
• artifact, optional, handoffs on commands come from the companion "artifact/optional/handoffs" issue.
• runtimes on scripts comes directly from the manifest (extensions post-#4010; add the same field to preset script entries for parity).
• All shorthand-key normalization (replaces/wraps/prepends/appends → strategy: "replace"|"wrap"|"prepend"|"append") is done server-side.

Alternatives Considered

• Fold everything into the companion specify artifact info --json command. Rejected — artifact info is per-artifact (walks one composition stack across all installed packs); info --json is per-source (walks one preset/extension across all its contributions). Both are needed and neither is a subset of the other.
• Fold everything into the companion preset list --json / extension list --json. Rejected — that surface is per-collection with summary counts; info is per-pack with full expansion. Different shape, different call pattern, different use cases (see Problem Statement).
• Emit YAML. Rejected — the whole point is to let the wizard drop js-yaml.
• Leave hook-phase / strategy shorthand un-normalized. Rejected — every consumer would reproduce the client-side logic from composition/collect.mjs and drift over time.

Component

Specify CLI (initialization, commands)

AI Agent (if applicable)

Not applicable

Use Cases

1. speckit-wizard-canvas deletes composition/collect.mjs::parseProvidesEntries and ::parseHookDeclarations, replacing them with JSON.parse(execFileSync("specify", ["preset", "info", "<id>", "--json"])) / specify extension info <id> --json. This is the change that removes the js-yaml dependency.
2. An IDE plugin renders hover-cards on command names by looking up the commands[] entry (description, artifact, handoffs).
3. A pre-commit check walks extension info --json's hooks[] to warn when two extensions register the same trigger at the same priority.

Acceptance Criteria

• specify preset info <id> --json and specify extension info <id> --json emit a single JSON object with top-level fields matching the companion list --json issue (id, name, description, version, author, priority, enabled, source) plus fully-expanded commands, templates, scripts arrays (and hooks for extensions) — not integer counts.
• Command entries include artifact, optional, handoffs (from the companion command-fields issue).
• Script entries include runtimes for both presets and extensions.
• Preset command/template/script entries include strategy; extension entries omit it (or set to "replace" for informational purposes).
• Shorthand keys (replaces/wraps/prepends/appends) are normalized server-side into strategy.
• Hook entries include trigger, targetCommand, sourcePath, optional, priority — phase/command shorthand normalized.
• All id values follow the stable-id scheme and are stable across reinstalls, matching the lookupId values emitted by specify artifact info --json.
• Unknown id → non-zero exit + stderr JSON error.
• Tests: schema round-trip, strategy normalization (all four shorthand forms), hook shorthand normalization, extension replace-only enforcement, handoffs frontmatter-merge, and id cross-reference with specify artifact info --json output.
• Docs: preset info / extension info sections in the CLI reference show the --json shape and normalization rules, plus a note contrasting info --json (per-pack, full expansion) with list --json (per-collection, count summary).

Additional Context

Direct replacement for plugins/spec-kit-copilot-wizard/extensions/speckit-wizard-canvas/composition/collect.mjs::parseProvidesEntries and ::parseHookDeclarations in github/spec-kit-copilot. Depends on the companion "artifact/optional/handoffs" and "stable id / lookupId" issues; benefits from the companion "structured source provenance" issue.