feat(skills): import 17 skills from local-dev; fix stale host

Consolidating the divergence between this repo and local-dev's embedded
~/dev/.skills/ (the two had drifted; the 19 overlapping skills were byte-identical).

- Import the 17 skills that existed only in local-dev: discovery-framing,
  stage-gate-review, web-shot, and the 14 superpowers-* skills. This repo is now
  the superset / single source of truth.
- SKILLS_INDEX.md: add rows for the 17.
- install.sh + Taskfile.yml: git.d-ma.be host (was stale gitea.d-ma.be, which
  broke the one-line curl|bash installer post-rename).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

superpowers-brainstorming/spec-document-reviewer-prompt.md

@@ -0,0 +1,49 @@
+# Spec Document Reviewer Prompt Template
+
+Use this template when dispatching a spec document reviewer subagent.
+
+**Purpose:** Verify the spec is complete, consistent, and ready for implementation planning.
+
+**Dispatch after:** Spec document is written to docs/superpowers/specs/
+
+```
+Task tool (general-purpose):
+  description: "Review spec document"
+  prompt: |
+    You are a spec document reviewer. Verify this spec is complete and ready for planning.
+
+    **Spec to review:** [SPEC_FILE_PATH]
+
+    ## What to Check
+
+    | Category | What to Look For |
+    |----------|------------------|
+    | Completeness | TODOs, placeholders, "TBD", incomplete sections |
+    | Consistency | Internal contradictions, conflicting requirements |
+    | Clarity | Requirements ambiguous enough to cause someone to build the wrong thing |
+    | Scope | Focused enough for a single plan — not covering multiple independent subsystems |
+    | YAGNI | Unrequested features, over-engineering |
+
+    ## Calibration
+
+    **Only flag issues that would cause real problems during implementation planning.**
+    A missing section, a contradiction, or a requirement so ambiguous it could be
+    interpreted two different ways — those are issues. Minor wording improvements,
+    stylistic preferences, and "sections less detailed than others" are not.
+
+    Approve unless there are serious gaps that would lead to a flawed plan.
+
+    ## Output Format
+
+    ## Spec Review
+
+    **Status:** Approved | Issues Found
+
+    **Issues (if any):**
+    - [Section X]: [specific issue] - [why it matters for planning]
+
+    **Recommendations (advisory, do not block approval):**
+    - [suggestions for improvement]
+```
+
+**Reviewer returns:** Status, Issues (if any), Recommendations