feat: opt-in usage telemetry + community intelligence platform (v0.8.6) (#210)

* feat: add gstack-telemetry-log and gstack-analytics scripts

Local telemetry infrastructure for gstack usage tracking.
gstack-telemetry-log appends JSONL events with skill name, duration,
outcome, session ID, and platform info. Supports off/anonymous/community
privacy tiers. gstack-analytics renders a personal usage dashboard
from local data.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: add telemetry preamble injection + opt-in prompt + epilogue

Extends generatePreamble() with telemetry start block (config read,
timer, session ID, .pending marker), opt-in prompt (gated by
.telemetry-prompted), and epilogue instructions for Claude to log
events after skill completion. Adds 5 telemetry tests.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* chore: regenerate all SKILL.md files with telemetry blocks

Automated regeneration from gen-skill-docs.ts changes. All skills
now include telemetry start block, opt-in prompt, and epilogue.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: add Supabase schema, edge functions, and SQL views

Telemetry backend infrastructure: telemetry_events table with RLS
(insert-only), installations table for retention tracking,
update_checks for install pings. Edge functions for update-check
(version + ping), telemetry-ingest (batch insert), and
community-pulse (weekly active count). SQL views for crash
clustering and skill co-occurrence sequences.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: add telemetry-sync, community-dashboard, and integration tests

gstack-telemetry-sync: fire-and-forget JSONL → Supabase sync with
privacy tier field stripping, batch limits, and cursor tracking.
gstack-community-dashboard: CLI tool querying Supabase for skill
popularity, crash clusters, and version distribution.
19 integration tests covering all telemetry scripts.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: session-specific .pending markers + crash_clusters view fix

Addresses Codex review findings:
- .pending race condition: use .pending-$SESSION_ID instead of
  shared .pending file to prevent concurrent session interference
- crash_clusters view: add total_occurrences and anonymous_occurrences
  columns since anonymous tier has no installation_id
- Added test: own session pending marker is not finalized

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: dual-attempt update check with Supabase install ping

Fires a parallel background curl to Supabase during the slow-path
version fetch. Logs upgrade_prompted event only on fresh fetches
(not cached replays) to avoid overcounting. GitHub remains the
primary version source — Supabase ping is fire-and-forget.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: integrate telemetry usage stats into /retro output

Retro now reads ~/.gstack/analytics/skill-usage.jsonl and includes
gstack usage metrics (skill run counts, top skills, success rate)
in the weekly retrospective output.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* chore: move 'Skill usage telemetry' to Completed in TODOS.md

Implemented in this branch: local JSONL logging, opt-in prompt,
privacy tiers, Supabase backend, community dashboard, /retro
integration.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: wire Supabase credentials and expose tables via Data API

Add supabase/config.sh with project URL and publishable key (safe to
commit — RLS restricts to INSERT only). Update telemetry-sync,
community-dashboard, and update-check to source the config and
include proper auth headers for the Supabase REST API.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: add SELECT RLS policies to migration for community dashboard reads

All telemetry data is anonymous (no PII), so public reads via the
publishable key are safe. Needed for the community dashboard to
query skill popularity, crash clusters, and version distribution.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* chore: bump version and changelog (v0.8.6)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: analytics backward-compatible with old JSONL format

Handle old-format events (no event_type field) alongside new format.
Skip hook_fire events. Fix grep -c whitespace issues and unbound
variable errors.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: map JSONL field names to Postgres columns in telemetry-sync

Local JSONL uses short names (v, ts, sessions) but the Supabase
table expects full names (schema_version, event_timestamp,
concurrent_sessions). Add sed mapping during field stripping.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: address Codex adversarial findings — cursor, opt-out, queries

- Sync cursor now advances on HTTP 2xx (not grep for "inserted")
- Update-check respects telemetry opt-out before pinging Supabase
- Dashboard queries use correct view column names (total_occurrences)
- Sync strips old-format "repo" field to prevent privacy leak

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* docs: add Privacy & Telemetry section to README

Transparent disclosure of what telemetry collects, what it never sends,
how to opt out, and a link to the schema so users can verify.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

codex/SKILL.md

@@ -34,8 +34,15 @@ echo "BRANCH: $_BRANCH"
 echo "PROACTIVE: $_PROACTIVE"
 _LAKE_SEEN=$([ -f ~/.gstack/.completeness-intro-seen ] && echo "yes" || echo "no")
 echo "LAKE_INTRO: $_LAKE_SEEN"
+_TEL=$(~/.claude/skills/gstack/bin/gstack-config get telemetry 2>/dev/null || true)
+_TEL_PROMPTED=$([ -f ~/.gstack/.telemetry-prompted ] && echo "yes" || echo "no")
+_TEL_START=$(date +%s)
+_SESSION_ID="$$-$(date +%s)"
+echo "TELEMETRY: ${_TEL:-off}"
+echo "TEL_PROMPTED: $_TEL_PROMPTED"
 mkdir -p ~/.gstack/analytics
 echo '{"skill":"codex","ts":"'$(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
+for _PF in ~/.gstack/analytics/.pending-*; do [ -f "$_PF" ] && ~/.claude/skills/gstack/bin/gstack-telemetry-log --event-type skill_run --skill _pending_finalize --outcome unknown --session-id "$_SESSION_ID" 2>/dev/null || true; break; done
 ```
 
 If `PROACTIVE` is `"false"`, do not proactively suggest gstack skills — only invoke
@@ -55,6 +62,27 @@ touch ~/.gstack/.completeness-intro-seen
 
 Only run `open` if the user says yes. Always run `touch` to mark as seen. This only happens once.
 
+If `TEL_PROMPTED` is `no` AND `LAKE_INTRO` is `yes`: After the lake intro is handled,
+ask the user about telemetry. Use AskUserQuestion:
+
+> gstack can share anonymous usage data (which skills you use, how long they take, crash info)
+> to help improve the project. No code, file paths, or repo names are ever sent.
+> Change anytime with `gstack-config set telemetry off`.
+
+Options:
+- A) Yes, share anonymous data (recommended)
+- B) No thanks
+
+If A: run `~/.claude/skills/gstack/bin/gstack-config set telemetry anonymous`
+If B: run `~/.claude/skills/gstack/bin/gstack-config set telemetry off`
+
+Always run:
+```bash
+touch ~/.gstack/.telemetry-prompted
+```
+
+This only happens once. If `TEL_PROMPTED` is `yes`, skip this entirely.
+
 ## AskUserQuestion Format
 
 **ALWAYS follow this structure for every AskUserQuestion call:**
@@ -154,6 +182,27 @@ ATTEMPTED: [what you tried]
 RECOMMENDATION: [what the user should do next]
 ```
 
+## Telemetry (run last)
+
+After the skill workflow completes (success, error, or abort), log the telemetry event.
+Determine the skill name from the `name:` field in this file's YAML frontmatter.
+Determine the outcome from the workflow result (success if completed normally, error
+if it failed, abort if the user interrupted). Run this bash:
+
+```bash
+_TEL_END=$(date +%s)
+_TEL_DUR=$(( _TEL_END - _TEL_START ))
+rm -f ~/.gstack/analytics/.pending-"$_SESSION_ID" 2>/dev/null || true
+~/.claude/skills/gstack/bin/gstack-telemetry-log \
+  --skill "SKILL_NAME" --duration "$_TEL_DUR" --outcome "OUTCOME" \
+  --used-browse "USED_BROWSE" --session-id "$_SESSION_ID" 2>/dev/null &
+```
+
+Replace `SKILL_NAME` with the actual skill name from frontmatter, `OUTCOME` with
+success/error/abort, and `USED_BROWSE` with true/false based on whether `$B` was used.
+If you cannot determine the outcome, use "unknown". This runs in the background and
+never blocks the user.
+
 ## Step 0: Detect base branch
 
 Determine which branch this PR targets. Use the result as "the base branch" in all subsequent steps.