refactor: drop 12 runtimes, keep Claude, Codex, OpenCode, Cursor, ZCode, Antigravity

Removes kilo, kimi, kimi-code, copilot, windsurf, augment, trae, qwen, hermes,
cline, codebuddy and pi end to end: capability descriptors, installer branches
and converters (bin/install.js 14.9k -> 11.2k lines), TypeScript converters,
hook surfaces and runtime homes, review lanes qwen/kimi-code, the two pi
migrations, Kimi payload normalization in the hook guards, dead hostBehaviors
vocabulary, launcher home probes, fixtures, runtime-specific tests and the
prose that presented them as supported.

Installer output for the six kept runtimes is byte-identical to before the
prune. The Kimi tool-vocabulary tests in workflow-guard, read-guard and
read-injection-scanner are left in place pending a decision.

scripts/build-hooks.js

@@ -44,9 +44,6 @@ const HOOKS_TO_COPY = [
   'msd-cursor-stop.js',
   'msd-cursor-subagent-start.js',
   'msd-cursor-subagent-stop.js',
-  // Windsurf/Cascade lifecycle hooks (ADR-1239/#2100 Stage 2): 2 blocking events
-  'msd-windsurf-pre-write.js',
-  'msd-windsurf-pre-command.js',
   // Claude Code FileChanged hook (#770) — hot-reloads msd config when
   // .planning/config.json changes mid-session. Must ship to dist so the
   // installer can copy it to the target hooks/ dir and register FileChanged.