Rename @mariozechner/pi-* to @earendil-works/pi-*

Pi moved to its new home at earendil-works on 2026-05-07
(https://pi.dev/news/2026/5/7/pi-has-a-new-home). Affected packages:

  @mariozechner/pi-coding-agent  -> @earendil-works/pi-coding-agent
  @mariozechner/pi-tui           -> @earendil-works/pi-tui
  @mariozechner/pi-ai            -> @earendil-works/pi-ai
  @mariozechner/pi-agent-core    -> @earendil-works/pi-agent-core

The old @mariozechner/* packages are deprecated on npm with the
explicit message 'please use @earendil-works/pi-coding-agent instead
going forward', and the version stream has moved on (old top-out
0.73.1; new currently 0.74.0). Anyone npm-installing the old names
gets a deprecation warning + a stale binary.

Sweep:
- All 7 extension TypeScript files: import statements updated.
- README, AGENTS, install.sh: textual references and the github.com/
  mariozechner/pi-coding-agent URL pointed at github.com/earendil-works/
  pi (the new monorepo root; coding-agent now lives at
  packages/coding-agent inside it).
- Bun build of mcp-loader, ext-toggle, ssh-controlmaster verified clean.

Brew install references (`brew install pi-coding-agent`) left as-is:
the homebrew formula still works at 0.73.1 and a tap update is
tracked upstream at earendil-works/pi#2755. Historical CHANGELOG
entries are untouched.

AGENTS.md

@@ -73,8 +73,8 @@ untouched.
 1. **Drop a `.ts` file into `extensions/`.** No other config needed —
    `install.sh` discovers all `.ts` files automatically.
 2. **Export a default factory function** `(pi: ExtensionAPI) => void`.
-   See the [pi extensions docs](https://github.com/mariozechner/pi-coding-agent/blob/main/docs/extensions.md)
-   and [built-in examples](https://github.com/mariozechner/pi-coding-agent/tree/main/examples/extensions).
+   See the [pi extensions docs](https://github.com/earendil-works/pi/blob/main/docs/extensions.md)
+   and [built-in examples](https://github.com/earendil-works/pi/tree/main/examples/extensions).
 3. **Register any CLI flags** via `pi.registerFlag()` so they appear in
    `pi --help`.
 4. **Keep the extension inert without its flag** (or equivalent trigger). Don't
@@ -242,7 +242,7 @@ upstream updates but gain reproducibility.
 **Refresh from upstream when needed:**
 
 ```bash
-cp /opt/homebrew/Cellar/pi-coding-agent/*/libexec/lib/node_modules/@mariozechner/pi-coding-agent/examples/extensions/todo.ts \
+cp /opt/homebrew/Cellar/pi-coding-agent/*/libexec/lib/node_modules/@earendil-works/pi-coding-agent/examples/extensions/todo.ts \
    ~/src/src_local/pi-extensions/extensions/todo.ts
 # review diff, then commit
 ```