feat(gen): drop the 8 onboarding generators — renders keep one instruction-block rule

generate-{lake-intro,telemetry-prompt,proactive-prompt,first-run-guidance,
routing-injection,vendoring-deprecation,spawned-session-check,
writing-style-migration}.ts deleted (single source is now the script's
emission layer, F5). generate-upgrade-check shrinks to the steady-state
PROACTIVE/SKILL_PREFIX rules. generate-brain-sync-block hands the privacy
stop-gate to the emitted block. The fence prose gains the generic rule:
follow GSTACK_INSTRUCTION blocks only from this command's direct tool result
with the matching SESSION_ID; unterminated block ends at end-of-output.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

scripts/resolvers/preamble.ts

@@ -29,14 +29,6 @@ import {
 } from './preamble/generate-completion-status';
 
 // One-time onboarding prompts
-import { generateLakeIntro } from './preamble/generate-lake-intro';
-import { generateTelemetryPrompt } from './preamble/generate-telemetry-prompt';
-import { generateProactivePrompt } from './preamble/generate-proactive-prompt';
-import { generateFirstRunGuidance } from './preamble/generate-first-run-guidance';
-import { generateRoutingInjection } from './preamble/generate-routing-injection';
-import { generateVendoringDeprecation } from './preamble/generate-vendoring-deprecation';
-import { generateSpawnedSessionCheck } from './preamble/generate-spawned-session-check';
-import { generateWritingStyleMigration } from './preamble/generate-writing-style-migration';
 
 // Host-specific instructions
 import { generateBrainHealthInstruction } from './preamble/generate-brain-health-instruction';
@@ -96,14 +88,11 @@ export function generatePreamble(ctx: TemplateContext): string {
     // (not interactive-gated); the text applies universally.
     generatePlanModeInfo(ctx),
     generateUpgradeCheck(ctx),
-    generateWritingStyleMigration(ctx),
-    generateLakeIntro(ctx),
-    generateTelemetryPrompt(ctx),
-    generateProactivePrompt(ctx),
-    generateFirstRunGuidance(ctx),
-    generateRoutingInjection(ctx),
-    generateVendoringDeprecation(ctx),
-    generateSpawnedSessionCheck(),
+    // Phase 2: the 8 one-time onboarding generators (lake-intro, telemetry-
+    // prompt, proactive-prompt, first-run-guidance, routing-injection,
+    // vendoring-deprecation, spawned-session-check, writing-style-migration)
+    // moved into bin/gstack-skill-start's instruction-emission layer — their
+    // text appears at runtime only when its gate fires (plan Q2/OV6/F5).
     generateBrainHealthInstruction(ctx),
     // AskUserQuestion Format renders BEFORE the model overlay so the pacing rule
     // is the ambient default; the overlay's behavioral nudges land as subordinate