Merge branch 'main' into garrytan/team-supabase-store

Brings in 48 commits from main (v0.15.7–v0.15.16): deterministic slugs,
TabSession refactor, pair-agent tunnel fix, content security layers,
community security wave, team-friendly install, interactive snapshots.

Conflict resolution:
- .gitignore: merged both sides (kept .factory/ + added .kiro/.opencode/
  .slate/.cursor/.openclaw/ from main)
- open-gstack-browser/SKILL.md: accepted main (renamed from .factory/)
- setup-team-sync/SKILL.md: regenerated via gen:skill-docs
- test/fixtures/golden/*: updated golden baselines for ship SKILL.md
- codex-ship-SKILL.md: accepted main (renamed from .factory/)
- package.json version: synced to VERSION (0.15.16.0)
- bin/gstack-uninstall: check settings file exists before claiming
  SessionStart hook removal (fixes false positive on clean systems)

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

test/fixtures/review-army-migration.sql

@@ -0,0 +1,5 @@
+-- Migration: Drop user email column
+-- WARNING: This migration is intentionally unsafe for testing
+ALTER TABLE users DROP COLUMN email;
+ALTER TABLE users DROP COLUMN phone_number;
+-- No backfill, no reversibility check, no data preservation

test/fixtures/review-army-n-plus-one.rb

@@ -0,0 +1,12 @@
+# N+1 query example — intentionally bad for testing
+class PostsController
+  def index
+    @posts = Post.all
+    @posts.each do |post|
+      # N+1: queries Author table for every post
+      puts post.author.name
+      # N+1: queries Comments table for every post
+      puts post.comments.count
+    end
+  end
+end