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.

tests/fixtures/install-tree/opencode.json

@@ -172,8 +172,6 @@
   "hooks/msd-statusline.js",
   "hooks/msd-update-banner.js",
   "hooks/msd-validate-commit.sh",
-  "hooks/msd-windsurf-pre-command.js",
-  "hooks/msd-windsurf-pre-write.js",
   "hooks/msd-workflow-guard.js",
   "hooks/msd-worktree-path-guard.js",
   "hooks/msd-write-guard.js",
@@ -474,7 +472,6 @@
   "msd-core/templates/config.json",
   "msd-core/templates/context.md",
   "msd-core/templates/continue-here.md",
-  "msd-core/templates/copilot-instructions.md",
   "msd-core/templates/dev-preferences.md",
   "msd-core/templates/discussion-log.md",
   "msd-core/templates/milestone-archive.md",