docs(v1): README hero reframe + writing-style + CHANGELOG + version bump to 1.0.0.0

README.md:
- Hero removes "600,000+ lines of production code" framing; replaces
  with the computed 2013-vs-2026 pro-rata multiple (via
  <!-- GSTACK-THROUGHPUT-PLACEHOLDER --> anchor, filled by the
  update-readme-throughput build step).
- Hiring callout: "ship real products at AI-coding speed" instead of
  "10K+ LOC/day."
- New Writing Style section (~80 words) between Quick start and
  Install: "v1 prompts = simpler" framing, outcome-language example,
  terse-mode opt-out, pointer to /plan-tune.

CLAUDE.md: one-paragraph Writing style (V1) note under project
conventions, linking to preamble resolver + V1 design docs.

CHANGELOG.md: V1 entry on top of v0.19.0.0 with user-facing narrative
(what changes, how to opt out, for-contributors notes). Mentions
scope reduction — pacing overhaul ships in V1.1.

CONTRIBUTING.md: one-paragraph note on jargon-list.json maintenance
(PR to add/remove terms; regenerate via gen:skill-docs).

VERSION + package.json: bump to 1.0.0.0.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

CONTRIBUTING.md

@@ -230,6 +230,25 @@ For template authoring best practices (natural language over bash-isms, dynamic
 
 To add a browse command, add it to `browse/src/commands.ts`. To add a snapshot flag, add it to `SNAPSHOT_FLAGS` in `browse/src/snapshot.ts`. Then rebuild.
 
+## Jargon list (V1 writing style)
+
+gstack's Writing Style section (injected into every tier-≥2 skill's preamble)
+glosses technical terms on first use per skill invocation. The list of terms
+that qualify for glossing lives at `scripts/jargon-list.json` — ~50 curated
+high-frequency terms (idempotent, race condition, N+1, backpressure, etc.).
+Terms not on the list are assumed plain-English enough.
+
+**Adding or removing a term:** open a PR editing `scripts/jargon-list.json`.
+Run `bun run gen:skill-docs` after the edit — terms are baked into every
+generated SKILL.md at gen time, so changes take effect only after regeneration.
+No runtime loading; no user-side override. The repo list is the source of truth.
+
+Good candidates for addition: high-frequency terms that non-technical users
+encounter in review output without context (common database/concurrency
+terminology, security jargon, frontend framework concepts). Don't add terms
+that only appear in one or two niche skills — the cost-to-value trade isn't
+worth the review overhead.
+
 ## Multi-host development
 
 gstack generates SKILL.md files for 8 hosts from one set of `.tmpl` templates.