chore: rebrand companion-os to clanker-agent

- Rename all package names from companion-* to clanker-*
- Update npm scopes from @mariozechner to @harivansh-afk
- Rename config directories .companion -> .clanker
- Rename environment variables COMPANION_* -> CLANKER_*
- Update all documentation, README files, and install scripts
- Rename package directories (companion-channels, companion-grind, companion-teams)
- Update GitHub URLs to harivansh-afk/clanker-agent
- Preserve full git history from companion-cloud monorepo

packages/coding-agent/test/session-selector-path-delete.test.ts

@@ -2,7 +2,7 @@ import {
   DEFAULT_EDITOR_KEYBINDINGS,
   EditorKeybindingsManager,
   setEditorKeybindings,
-} from "@mariozechner/companion-tui";
+} from "@mariozechner/clanker-tui";
 import { beforeAll, beforeEach, describe, expect, it } from "vitest";
 import { KeybindingsManager } from "../src/core/keybindings.js";
 import type { SessionInfo } from "../src/core/session-manager.js";