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.

README.md

@@ -1,6 +1,6 @@
 # pi-extensions
 
-Custom and modified extensions for the [pi coding-agent](https://github.com/mariozechner/pi-coding-agent).
+Custom and modified extensions for the [pi coding-agent](https://github.com/earendil-works/pi).
 
 This repo is the single source of truth for extensions that aren't suitable for general publishing — personal workflow tweaks, modified versions of built-in examples, and extensions written for specific infrastructure. Symlinked into `~/.pi/agent/extensions/` so pi loads them automatically.
 
@@ -266,7 +266,7 @@ Generic MCP server loader. Reads an `mcp` block from `~/.pi/agent/settings.json`
 
 UX matches `/ext`: **space** stages a toggle, **enter** writes back to `settings.json` and reloads pi, **esc** cancels. Toggling re-enables a previously-disabled server by removing the explicit `enabled` key (the default is `true`).
 
-Each extension is a TypeScript module loaded by [jiti](https://github.com/unjs/jiti) — no compilation step. See the [pi extensions docs](https://github.com/mariozechner/pi-coding-agent/blob/main/docs/extensions.md) and the [built-in examples](https://github.com/mariozechner/pi-coding-agent/tree/main/examples/extensions) for the API surface.
+Each extension is a TypeScript module loaded by [jiti](https://github.com/unjs/jiti) — no compilation step. See the [pi extensions docs](https://github.com/earendil-works/pi/blob/main/docs/extensions.md) and the [built-in examples](https://github.com/earendil-works/pi/tree/main/examples/extensions) for the API surface.
 
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