feat(aircoding): AirCoding V2 baseline — deterministic multi-agent architecture

Forked from OpenCode v1.17.4 with multi-agent system:
- 5 agents: aircoding, scheduler, worker, architect, reviewer
- Deterministic DAG scheduling engine (coordinator_tick)
- Tool whitelists as hard enforcement
- AirCoding validation plugin
- V1 requirements: C4 docs, ADR, AGENTS.md, debug-log.md
- Design documents in docs/

packages/app/src/components/prompt-input/files.ts

@@ -0,0 +1,98 @@
+import { ACCEPTED_FILE_TYPES, ACCEPTED_IMAGE_TYPES } from "@/constants/file-picker"
+
+export { ACCEPTED_FILE_TYPES }
+
+type AttachmentPicker = (
+  options: {
+    defaultPath?: string
+    multiple?: boolean
+    accept?: string[]
+  },
+  onFile: (file: File) => Promise<unknown>,
+) => Promise<void>
+
+export function pickAttachmentFiles(input: {
+  picker?: AttachmentPicker
+  directory: () => string
+  fallback: () => void
+  onFile: (file: File) => Promise<unknown>
+  onError: (error: unknown) => void
+}) {
+  if (!input.picker) {
+    input.fallback()
+    return
+  }
+  void input
+    .picker(
+      {
+        defaultPath: input.directory(),
+        multiple: true,
+        accept: ACCEPTED_FILE_TYPES,
+      },
+      input.onFile,
+    )
+    .catch(input.onError)
+}
+
+const IMAGE_MIMES = new Set(ACCEPTED_IMAGE_TYPES)
+const IMAGE_EXTS = new Map([
+  ["gif", "image/gif"],
+  ["jpeg", "image/jpeg"],
+  ["jpg", "image/jpeg"],
+  ["png", "image/png"],
+  ["webp", "image/webp"],
+])
+const TEXT_MIMES = new Set([
+  "application/json",
+  "application/ld+json",
+  "application/toml",
+  "application/x-toml",
+  "application/x-yaml",
+  "application/xml",
+  "application/yaml",
+])
+
+const SAMPLE = 4096
+
+function kind(type: string) {
+  return type.split(";", 1)[0]?.trim().toLowerCase() ?? ""
+}
+
+function ext(name: string) {
+  const idx = name.lastIndexOf(".")
+  if (idx === -1) return ""
+  return name.slice(idx + 1).toLowerCase()
+}
+
+function textMime(type: string) {
+  if (!type) return false
+  if (type.startsWith("text/")) return true
+  if (TEXT_MIMES.has(type)) return true
+  if (type.endsWith("+json")) return true
+  return type.endsWith("+xml")
+}
+
+function textBytes(bytes: Uint8Array) {
+  if (bytes.length === 0) return true
+  let count = 0
+  for (const byte of bytes) {
+    if (byte === 0) return false
+    if (byte < 9 || (byte > 13 && byte < 32)) count += 1
+  }
+  return count / bytes.length <= 0.3
+}
+
+export async function attachmentMime(file: File) {
+  const type = kind(file.type)
+  if (IMAGE_MIMES.has(type)) return type
+  if (type === "application/pdf") return type
+
+  const suffix = ext(file.name)
+  const fallback = IMAGE_EXTS.get(suffix) ?? (suffix === "pdf" ? "application/pdf" : undefined)
+  if ((!type || type === "application/octet-stream") && fallback) return fallback
+
+  if (textMime(type)) return "text/plain"
+  const bytes = new Uint8Array(await file.slice(0, SAMPLE).arrayBuffer())
+  if (!textBytes(bytes)) return
+  return "text/plain"
+}