feat(quick-260421-u38): sync upstream GSD v1.38.3 sketch/spike updates

Ports the substantive sketch/spike changes from upstream 1.38.3:
- Frontier mode — running /gsd:sketch or /gsd:spike with no argument
  (or literal "frontier") analyzes existing sketch/spike landscape and
  proposes consistency/frontier targets.
- Extended allowed-tools: WebSearch, WebFetch, context7 (resolve-library-id,
  query-docs) for grounding sketches/spikes in real API surfaces.
- Updated descriptions and argument hints reflecting the dual-mode API.

Also fixes a skip-pattern bug in bin/maintenance/rewrite-command-namespace.cjs
surfaced by this sync: the pattern only covered `.planning/milestones/v1.0-`
and the stale `.planning/phases/04-` path, missing the v1.1 archive at
`.planning/milestones/v1.1-phases/`. First run wrongly rewrote historical
archive files; skip pattern now generalized to `v\d+\.` to match any
versioned milestone archive.

Not ported:
- Upstream's `get-shit-done/workflows/sketch.md`, `spike.md`,
  `sketch-wrap-up.md`, `spike-wrap-up.md` (184-414 diff lines).
  Plugin has no workflows/ directory; all @~/.claude/get-shit-done/workflows/*
  refs in plugin SKILL.md files dangle by design. This structural drift
  is v1.2 Phase 7's target — not in scope for this sync.

Author: jnuyens

bin/maintenance/rewrite-command-namespace.cjs

@@ -61,8 +61,8 @@ const allFiles = execSync('git ls-files', { encoding: 'utf-8' }).trim().split('\
 const textExt = /\.(md|json|cjs|js|ts|tsx|txt|yml|yaml|sh|html)$/i;
 const skipDirs = [
   /^_research\//,
-  /^\.planning\/milestones\/v1\.0-/,
-  /^\.planning\/phases\/04-/,
+  /^\.planning\/milestones\/v\d+\./,        // any archived milestone (v1.0-*, v1.1-phases/, v1.2-phases/, ...)
+  /^\.planning\/phases\/04-/,               // kept for reference; Phase 04 was moved to v1.1-phases/ above
   /^\.planning\/quick\/2604(0[7-9]|1[0-8])-/, // pre-2026-04-19 quick tasks
 ];
 const included = allFiles.filter(f => {

skills/gsd-sketch/SKILL.md

@@ -1,7 +1,7 @@
 ---
 name: gsd:sketch
-description: Rapidly sketch UI/design ideas using throwaway HTML mockups with multi-variant exploration
-argument-hint: "<design idea to explore> [--quick]"
+description: Sketch UI/design ideas with throwaway HTML mockups, or propose what to sketch next (frontier mode)
+argument-hint: "[design idea to explore] [--quick] [--text] or [frontier]"
 allowed-tools:
   - Read
   - Write
@@ -10,11 +10,20 @@ allowed-tools:
   - Grep
   - Glob
   - AskUserQuestion
+  - WebSearch
+  - WebFetch
+  - mcp__context7__resolve-library-id
+  - mcp__context7__query-docs
 ---
 <objective>
 Explore design directions through throwaway HTML mockups before committing to implementation.
 Each sketch produces 2-3 variants for comparison. Sketches live in `.planning/sketches/` and
-integrate with GSD commit patterns, state tracking, and handoff workflows.
+integrate with GSD commit patterns, state tracking, and handoff workflows. Loads spike
+findings to ground mockups in real data shapes and validated interaction patterns.
+
+Two modes:
+- **Idea mode** (default) — describe a design idea to sketch
+- **Frontier mode** (no argument or "frontier") — analyzes existing sketch landscape and proposes consistency and frontier sketches
 
 Does not require `/gsd:new-project` — auto-creates `.planning/sketches/` if needed.
 </objective>
@@ -41,5 +50,5 @@ Design idea: $ARGUMENTS
 
 <process>
 Execute the sketch workflow from @~/.claude/get-shit-done/workflows/sketch.md end-to-end.
-Preserve all workflow gates (intake, decomposition, variant evaluation, MANIFEST updates, commit patterns).
+Preserve all workflow gates (intake, decomposition, target stack research, variant evaluation, MANIFEST updates, commit patterns).
 </process>

skills/gsd-spike/SKILL.md

@@ -1,7 +1,7 @@
 ---
 name: gsd:spike
-description: Rapidly spike an idea with throwaway experiments to validate feasibility before planning
-argument-hint: "<idea to validate> [--quick]"
+description: Spike an idea through experiential exploration, or propose what to spike next (frontier mode)
+argument-hint: "[idea to validate] [--quick] [--text] or [frontier]"
 allowed-tools:
   - Read
   - Write
@@ -10,11 +10,20 @@ allowed-tools:
   - Grep
   - Glob
   - AskUserQuestion
+  - WebSearch
+  - WebFetch
+  - mcp__context7__resolve-library-id
+  - mcp__context7__query-docs
 ---
 <objective>
-Rapid feasibility validation through focused, throwaway experiments. Each spike answers one
-specific question with observable evidence. Spikes live in `.planning/spikes/` and integrate
-with GSD commit patterns, state tracking, and handoff workflows.
+Spike an idea through experiential exploration — build focused experiments to feel the pieces
+of a future app, validate feasibility, and produce verified knowledge for the real build.
+Spikes live in `.planning/spikes/` and integrate with GSD commit patterns, state tracking,
+and handoff workflows.
+
+Two modes:
+- **Idea mode** (default) — describe an idea to spike
+- **Frontier mode** (no argument or "frontier") — analyzes existing spike landscape and proposes integration and frontier spikes
 
 Does not require `/gsd:new-project` — auto-creates `.planning/spikes/` if needed.
 </objective>
@@ -33,9 +42,10 @@ Idea: $ARGUMENTS
 
 **Available flags:**
 - `--quick` — Skip decomposition/alignment, jump straight to building. Use when you already know what to spike.
+- `--text` — Use plain-text numbered lists instead of AskUserQuestion (for non-Claude runtimes).
 </context>
 
 <process>
 Execute the spike workflow from @~/.claude/get-shit-done/workflows/spike.md end-to-end.
-Preserve all workflow gates (decomposition, risk ordering, verification, MANIFEST updates, commit patterns).
+Preserve all workflow gates (prior spike check, decomposition, research, risk ordering, observability assessment, verification, MANIFEST updates, commit patterns).
 </process>