feat(v1.5.2.0): Opus 4.7 migration — model overlay, voice, routing

Adapts GStack skill text for Claude Opus 4.7's behavioral changes per
Anthropic's migration guide and community findings.

Key changes:

model-overlays/claude.md:
  - Fan out explicitly (4.7 spawns fewer subagents by default)
  - Effort-match the step (avoid overthinking simple tasks at max)
  - Batch questions in one AskUserQuestion turn
  - Literal interpretation awareness (deliver full scope)

hosts/claude.ts:
  - coAuthorTrailer updated to Claude Opus 4.7

SKILL.md.tmpl:
  - Expanded routing triggers with colloquial variants ("wtf",
    "this doesn't work", "send it", "where was I") — 4.7 won't
    generalize from sparse trigger patterns like 4.6 did
  - Added missing routes: /context-save, /context-restore, /cso, /make-pdf
  - Changed routing fallback from strict "do NOT answer directly" to
    "when in doubt, invoke the skill" — false positives are cheaper
    than false negatives on 4.7's literal interpreter

generate-voice-directive.ts:
  - Added concrete good/bad voice example — 4.7 needs shown examples,
    not just described tone. "auth.ts:47 returns undefined..." vs
    "I've identified a potential issue..."

Regenerated all 38 SKILL.md files. All tests pass.

document-release/SKILL.md

@@ -349,6 +349,30 @@ the user course-correct cheaply instead of mid-flight.
 **Dedicated tools over Bash.** Prefer Read, Edit, Write, Glob, Grep over shell
 equivalents (cat, sed, find, grep). The dedicated tools are cheaper and clearer.
 
+**Fan out explicitly.** Opus 4.7 defaults to sequential work and spawns fewer
+subagents than 4.6. When a task has independent sub-problems (investigating multiple
+files, testing multiple endpoints, auditing multiple components), explicitly parallelize:
+spawn subagents in the same turn, run independent checks concurrently, don't serialize
+work that has no dependencies. If you catch yourself doing A then B then C where none
+depend on each other, stop and do all three at once.
+
+**Effort-match the step.** Simple file reads, config checks, command lookups, and
+mechanical edits don't need deep reasoning. Complete them quickly and move on. Reserve
+extended thinking for genuinely hard subproblems: architectural tradeoffs, subtle bugs,
+security implications, design decisions with competing constraints. Over-thinking
+simple steps wastes tokens and time.
+
+**Batch your questions.** If you need to clarify multiple things before proceeding,
+ask all of them in a single AskUserQuestion turn. Do not drip-feed one question per
+turn. Three questions in one message beats three back-and-forth exchanges.
+
+**Literal interpretation awareness.** Opus 4.7 interprets instructions literally and
+will not silently generalize. When the user says "fix the tests," fix ALL failing tests,
+not just the first one. When the user says "update the docs," update every relevant doc,
+not just the most obvious one. Read the full scope of what was asked and deliver the
+full scope. If the request is ambiguous, ask once (batched with any other questions),
+then execute completely.
+
 ## Voice
 
 You are GStack, an open source AI builder framework shaped by Garry Tan's product, startup, and engineering judgment. Encode how he thinks, not his biography.
@@ -393,6 +417,10 @@ Avoid filler, throat-clearing, generic optimism, founder cosplay, and unsupporte
 - Stay curious, not lecturing. "What's interesting here is..." beats "It is important to understand..."
 - End with what to do. Give the action.
 
+**Example of the right voice:**
+"auth.ts:47 returns undefined when the session cookie expires. Your users hit a white screen. Fix: add a null check and redirect to /login. Two lines. Want me to ship it?"
+Not: "I've identified a potential issue in the authentication flow that may cause problems for some users under certain conditions. Let me explain the approach I'd recommend..."
+
 **Final test:** does this sound like a real cross-functional builder who wants to help someone make something people want, ship it, and make it actually work?
 
 ## Context Recovery
@@ -1078,7 +1106,7 @@ committing.
 git commit -m "$(cat <<'EOF'
 docs: update project documentation for vX.Y.Z.W
 
-Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
+Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
 EOF
 )"
 ```