build: prune stale bundle chunks before rebuilding dists

Stale content-hashed chunks from earlier builds accumulate in dist/ and
carry old schema-fence values; anyone verifying a rebuild by grepping
dist/*.js finds a mix of old and new fences and reaches the wrong
conclusion (tonight's fleet seat-death postmortem). Deleting the bundle
entrypoints and hashed chunks before bun build makes the on-disk chunk
set exactly the referenced set, so an artifact grep is trustworthy.
Declaration trees and the compiled TUI are untouched.

Author: ualtinok

packages/pi-plugin/package.json

@@ -26,7 +26,7 @@
 		"README.md"
 	],
 	"scripts": {
-		"build": "bun build src/index.ts src/subagent-entry.ts --outdir dist --target node --format esm --splitting --external @earendil-works/pi-coding-agent --external @earendil-works/pi-tui --external @huggingface/transformers --external node:sqlite",
+		"build": "rm -f dist/index.js dist/subagent-entry.js dist/*-*.js && bun build src/index.ts src/subagent-entry.ts --outdir dist --target node --format esm --splitting --external @earendil-works/pi-coding-agent --external @earendil-works/pi-tui --external @huggingface/transformers --external node:sqlite",
 		"typecheck": "tsc --noEmit",
 		"test": "bun test",
 		"lint": "biome check src",

packages/plugin/package.json

@@ -30,7 +30,7 @@
     "README.md"
   ],
   "scripts": {
-    "build": "bun run build:tui && bun build src/index.ts --outdir dist --target node --format esm --splitting --external @opencode-ai/plugin --external @huggingface/transformers --external onnxruntime-web --external bun:sqlite --external node:sqlite && tsc --emitDeclarationOnly",
+    "build": "bun run build:tui && rm -f dist/index.js dist/*-*.js && bun build src/index.ts --outdir dist --target node --format esm --splitting --external @opencode-ai/plugin --external @huggingface/transformers --external onnxruntime-web --external bun:sqlite --external node:sqlite && tsc --emitDeclarationOnly",
     "build:tui": "bun scripts/build-tui.ts",
     "check:tui-compiled": "bun run build:tui && git diff --exit-code -- src/tui-compiled && test -z \"$(git status --porcelain -- src/tui-compiled)\"",
     "typecheck": "tsc --noEmit && tsc -p tsconfig.scripts.json",