docs: deprecate vendoring, document team mode, clean up uninstall

- README: replace "Step 2: Add to your repo" vendoring instructions
  with team mode (./setup --team + gstack-team-init)
- CLAUDE.md: rename "Vendored symlink awareness" to "Dev symlink
  awareness", add deprecation note
- CONTRIBUTING.md: remove vendoring language from prefix section
- bin/gstack-uninstall: clean up SessionStart hook on uninstall

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

CLAUDE.md

@@ -186,10 +186,10 @@ failure modes. The sidebar spans 5 files across 2 codebases (extension + server)
 with non-obvious ordering dependencies. The doc exists to prevent the kind of
 silent failures that come from not understanding the cross-component flow.
 
-## Vendored symlink awareness
+## Dev symlink awareness
 
 When developing gstack, `.claude/skills/gstack` may be a symlink back to this
-working directory (gitignored). This means skill changes are **live immediately** —
+working directory (gitignored). This means skill changes are **live immediately**,
 great for rapid iteration, risky during big refactors where half-written skills
 could break other Claude Code sessions using gstack concurrently.
 
@@ -204,9 +204,11 @@ symlink or a real copy. If it's a symlink to your working directory, be aware th
 with a SKILL.md symlink inside (e.g., `qa/SKILL.md -> gstack/qa/SKILL.md`). This
 ensures Claude discovers them as top-level skills, not nested under `gstack/`.
 Names are either short (`qa`) or namespaced (`gstack-qa`), controlled by
-`skill_prefix` in `~/.gstack/config.yaml`. When vendoring into a project, run
-`./setup` after symlinking to create the per-skill directories. Pass `--no-prefix`
-or `--prefix` to skip the interactive prompt.
+`skill_prefix` in `~/.gstack/config.yaml`. Pass `--no-prefix` or `--prefix` to
+skip the interactive prompt.
+
+**Note:** Vendoring gstack into a project's repo is deprecated. Use global install
++ `./setup --team` instead. See README.md for team mode instructions.
 
 **For plan reviews:** When reviewing plans that modify skill templates or the
 gen-skill-docs pipeline, consider whether the changes should be tested in isolation

CONTRIBUTING.md

@@ -367,7 +367,7 @@ to `gstack/...`, so they'll resolve to the global install automatically.
 
 ### Switching prefix mode
 
-If you vendored gstack with one prefix setting and want to switch:
+If you installed gstack with one prefix setting and want to switch:
 
 ```bash
 cd .claude/skills/gstack && ./setup --no-prefix   # switch to /qa, /ship

README.md

@@ -48,11 +48,23 @@ Open Claude Code and paste this. Claude does the rest.
 
 > Install gstack: run **`git clone --single-branch --depth 1 https://github.com/garrytan/gstack.git ~/.claude/skills/gstack && cd ~/.claude/skills/gstack && ./setup`** then add a "gstack" section to CLAUDE.md that says to use the /browse skill from gstack for all web browsing, never use mcp\_\_claude-in-chrome\_\_\* tools, and lists the available skills: /office-hours, /plan-ceo-review, /plan-eng-review, /plan-design-review, /design-consultation, /design-shotgun, /design-html, /review, /ship, /land-and-deploy, /canary, /benchmark, /browse, /connect-chrome, /qa, /qa-only, /design-review, /setup-browser-cookies, /setup-deploy, /retro, /investigate, /document-release, /codex, /cso, /autoplan, /plan-devex-review, /devex-review, /careful, /freeze, /guard, /unfreeze, /gstack-upgrade, /learn. Then ask the user if they also want to add gstack to the current project so teammates get it.
 
-### Step 2: Add to your repo so teammates get it (optional)
+### Step 2: Team mode — auto-update for shared repos (recommended)
 
-> Add gstack to this project: run **`cp -Rf ~/.claude/skills/gstack .claude/skills/gstack && rm -rf .claude/skills/gstack/.git && cd .claude/skills/gstack && ./setup`** then add a "gstack" section to this project's CLAUDE.md that says to use the /browse skill from gstack for all web browsing, never use mcp\_\_claude-in-chrome\_\_\* tools, lists the available skills: /office-hours, /plan-ceo-review, /plan-eng-review, /plan-design-review, /design-consultation, /design-shotgun, /design-html, /review, /ship, /land-and-deploy, /canary, /benchmark, /browse, /connect-chrome, /qa, /qa-only, /design-review, /setup-browser-cookies, /setup-deploy, /retro, /investigate, /document-release, /codex, /cso, /autoplan, /plan-devex-review, /devex-review, /careful, /freeze, /guard, /unfreeze, /gstack-upgrade, /learn, and tells Claude that if gstack skills aren't working, run `cd .claude/skills/gstack && ./setup` to build the binary and register skills.
+Every developer installs globally, updates happen automatically:
 
-Real files get committed to your repo (not a submodule), so `git clone` just works. Everything lives inside `.claude/`. Nothing touches your PATH or runs in the background.
+```bash
+cd ~/.claude/skills/gstack && ./setup --team
+```
+
+Then bootstrap your repo so teammates get it:
+
+```bash
+cd <your-repo>
+~/.claude/skills/gstack/bin/gstack-team-init required  # or: optional
+git add .claude/ CLAUDE.md && git commit -m "require gstack for AI-assisted work"
+```
+
+No vendored files in your repo, no version drift, no manual upgrades. Every Claude Code session starts with a fast auto-update check (throttled to once/hour, network-failure-safe, completely silent).
 
 > **Contributing or need full history?** The commands above use `--depth 1` for a fast install. If you plan to contribute or need full git history, do a full clone instead:
 > ```bash

bin/gstack-uninstall

@@ -227,6 +227,13 @@ if [ -n "$_GIT_ROOT" ]; then
   fi
 fi
 
+# ─── Remove SessionStart hook from Claude Code settings ─────
+SETTINGS_HOOK="$(dirname "$0")/gstack-settings-hook"
+SESSION_UPDATE="$(dirname "$0")/gstack-session-update"
+if [ -x "$SETTINGS_HOOK" ]; then
+  "$SETTINGS_HOOK" remove "$SESSION_UPDATE" 2>/dev/null && REMOVED+=("SessionStart hook") || true
+fi
+
 # ─── Remove global state ────────────────────────────────────
 if [ "$KEEP_STATE" -eq 0 ] && [ -d "$STATE_DIR" ]; then
   rm -rf "$STATE_DIR"