fix(telemetry): accurate consent copy + JSON-safe repo basename

The telemetry consent prompt promised "no repo names" while the preamble
epilogue records the repo basename in the local skill-usage.jsonl. It is
already stripped before any remote upload, so it never left the machine, but
the copy was unqualified. Reword it to state repo name is local-only and
stripped before upload.

Also sanitize the basename to [a-zA-Z0-9._-] before it goes into the
hand-built JSON, so a repo directory name containing quotes or newlines can
neither break the JSON nor leak a fragment past the regex stripper.

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

scripts/resolvers/preamble/generate-preamble-bash.ts

@@ -48,7 +48,7 @@ _QUESTION_TUNING=$(${ctx.paths.binDir}/gstack-config get question_tuning 2>/dev/
 echo "QUESTION_TUNING: $_QUESTION_TUNING"
 mkdir -p ~/.gstack/analytics
 if [ "$_TEL" != "off" ]; then
-echo '{"skill":"${ctx.skillName}","ts":"'$(date -u +%Y-%m-%dT%H:%M:%SZ)'","repo":"'$(basename "$(git rev-parse --show-toplevel 2>/dev/null)" 2>/dev/null || echo "unknown")'"}'  >> ~/.gstack/analytics/skill-usage.jsonl 2>/dev/null || true
+echo '{"skill":"${ctx.skillName}","ts":"'$(date -u +%Y-%m-%dT%H:%M:%SZ)'","repo":"'$(_repo=$(basename "$(git rev-parse --show-toplevel 2>/dev/null)" 2>/dev/null | tr -cd 'a-zA-Z0-9._-'); echo "\${_repo:-unknown}")'"}'  >> ~/.gstack/analytics/skill-usage.jsonl 2>/dev/null || true
 fi
 for _PF in $(find ~/.gstack/analytics -maxdepth 1 -name '.pending-*' 2>/dev/null); do
   if [ -f "$_PF" ]; then

scripts/resolvers/preamble/generate-telemetry-prompt.ts

@@ -3,7 +3,7 @@ import type { TemplateContext } from '../types';
 export function generateTelemetryPrompt(ctx: TemplateContext): string {
   return `If \`TEL_PROMPTED\` is \`no\` AND \`LAKE_INTRO\` is \`yes\`: ask telemetry once via AskUserQuestion:
 
-> Help gstack get better. Share usage data only: skill, duration, crashes, stable device ID. No code, file paths, or repo names.
+> Help gstack get better. Share usage data only: skill, duration, crashes, stable device ID. No code or file paths. Your repo name is recorded locally only and stripped before any upload.
 
 Options:
 - A) Help gstack get better! (recommended)