feat: bump pi coding agent to 0.79.1 for Claude Fable 5 support

Update @earendil-works/pi-coding-agent and @earendil-works/pi-ai from
^0.78.0 to ^0.79.1 across cli, engine, and dashboard. This brings in
Claude Fable 5 (claude-fable-5) on the Anthropic and Amazon Bedrock
providers.

Fusion's model picker is registry-driven (/api/models -> pi ModelRegistry,
filtered by provider, not model id), so Fable surfaces automatically for
users with Anthropic or Claude CLI auth configured — no Fusion-side model
list change needed.

Verified: all core packages typecheck clean against 0.79.1; boot smoke
(fn --help, /api/health 200, clean shutdown) passes.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/cli/package.json

@@ -57,8 +57,8 @@
     "test:pre-release": "pnpm test:slow-cli && pnpm test:build-exe"
   },
   "dependencies": {
-    "@earendil-works/pi-ai": "^0.78.0",
-    "@earendil-works/pi-coding-agent": "^0.78.0",
+    "@earendil-works/pi-ai": "^0.79.1",
+    "@earendil-works/pi-coding-agent": "^0.79.1",
     "dockerode": "^4.0.12",
     "express": "^5.1.0",
     "i18next": "^26.3.1",