refactor: split pi-generic config into pi-toolkit repo

Parallel to the opencode-toolkit split earlier today. Pi's own config
(keybindings, shell env loader, settings template) moves to a new
sibling repo so opencode-devbox's mempalace opt-out can build slim
containers that include pi without dragging in chromadb + embedding
models (~300 MB).

What moved to pi-toolkit (https://gitea.jordbo.se/joakimp/pi-toolkit):
- extensions/pi/keybindings.json          (mosh/tmux newline fix)
- extensions/pi/pi-env.zsh                (sources ~/.config/pi/.env)
- extensions/pi/settings.example.json     (Bedrock template)
- install.sh::install_pi_keybindings      (symlink step)
- install.sh::install_pi_env_loader       (cp step + bash fallback)
- install.sh::check_pi_settings           (probe)
- install.sh::check_aws_env               (probe)

What stays here (this is the pi\u2194mempalace bridge, mempalace-side):
- extensions/pi/mempalace.ts              (the MCP extension)
- install.sh::install_pi_extension        (symlink step)
- NEW: install.sh::check_pi_toolkit       (probe: warns if pi is
                                           installed but pi-toolkit's
                                           artifacts are missing, with
                                           git-clone pointer)

install.sh shrank from 520 to 403 lines. Uninstall mirror correctly
does NOT touch pi-toolkit-owned files (explicit comment).

Docs updated:
- extensions/pi/README.md: rewritten as 'pi\u2194MemPalace MCP bridge',
  recipe becomes 'Deploying pi with mempalace' (pi-toolkit step 3,
  this repo step 5).
- AGENTS.md: Structure block + 'What install.sh does' section reflect
  the narrower scope and list the four things that moved out.
- README.md: repo-contents line + Setup section's deploy summary.

Verified on tor-ms22: full install\u2192uninstall\u2192reinstall lifecycle clean.
After mempalace-toolkit uninstall, pi-toolkit artifacts
(~/.pi/agent/keybindings.json, ~/.oh-my-zsh/custom/pi-env.zsh) remain
intact \u2014 correctly untouched. check_pi_toolkit probe fires green when
both exist.

AGENTS.md

@@ -19,12 +19,9 @@ bin/
   mempalace-pi-session  # pi session → MemPalace bridge (bash + inline Python)
 contrib/                # systemd / launchd / cron templates for scheduling feeders
 extensions/
-  pi/                   # pi coding-agent bring-up: MCP bridge, keybindings, settings template
+  pi/                   # pi↔mempalace MCP bridge (bridge-only; pi's own config is in the pi-toolkit repo)
     mempalace.ts        # Symlinked into ~/.pi/agent/extensions/ (MCP <→ pi glue)
-    keybindings.json    # Symlinked into ~/.pi/agent/ (mosh/tmux newline fix)
-    pi-env.zsh          # Copied into ~/.oh-my-zsh/custom/ or sourced from .bashrc (loads ~/.config/pi/.env)
-    settings.example.json # Template; user copies + edits (pi rewrites settings.json at runtime)
-    README.md           # Extension internals, schema-passthrough gotcha, env setup
+    README.md           # Bridge internals, Type.Unsafe gotcha, pi+mempalace deploy recipe
 ```
 
 ## What `install.sh` does
@@ -37,19 +34,25 @@ Idempotent, safe to re-run. Always:
 Gated on pi being installed (`~/.pi/agent/extensions/` exists):
 
 - Symlinks `extensions/pi/mempalace.ts` into `~/.pi/agent/extensions/`. Backs up any real file in the way.
-- Symlinks `extensions/pi/keybindings.json` into `~/.pi/agent/`. Backs up any real file in the way.
-- `settings.example.json` is **not** symlinked — pi rewrites `settings.json` at runtime, so we'd dirty the repo. Installer warns if `settings.json` is missing and prints the `cp` command.
 
 Probes (never halt, `warn` + `return 0`):
 
 - `~/.local/bin` is on `$PATH`.
 - `~/.config/opencode/instructions/mempalace.md` exists (opencode wake-up protocol).
 - `mempalace` is registered as an MCP server in `~/.config/opencode/opencode.json`.
-- `~/.pi/agent/settings.json` exists (if pi is installed).
-- `AWS_PROFILE`/`AWS_REGION` set, but only if `settings.json` exists *and* selects `amazon-bedrock`. Silent otherwise.
+- If pi is installed: pi-toolkit artifacts (`~/.pi/agent/keybindings.json` symlink, `~/.oh-my-zsh/custom/pi-env.zsh`) exist. Warns with a `git clone ssh://...pi-toolkit.git` pointer if missing.
 
 All non-destructive: if something is already in place and points into this repo, prints "already linked" and moves on. If a non-symlink real file is in the way, backs it up with a timestamp.
 
+**Not handled here any more** (split to [`pi-toolkit`](https://gitea.jordbo.se/joakimp/pi-toolkit) on 2026-05-05):
+
+- `keybindings.json` symlink into `~/.pi/agent/`
+- `pi-env.zsh` cp into `~/.oh-my-zsh/custom/`
+- `settings.example.json` template + `check_pi_settings` probe
+- `check_aws_env` probe
+
+Those are pi-generic concerns. This toolkit installs **only** the pi↔mempalace MCP bridge on top of whatever pi-toolkit set up.
+
 
 ## Conventions