feat(vfs): add lazy vfs + remove dynamic fields for prompt caching hits (#5138)

* feat(vfs): add lazy vfs + remove dynamic fields for prompt caching hits

* feat(vfs): send typed workspace snapshot for append-only deltas

Build the workspace inventory from the primary db (fixes replica-lag staleness)
and emit it as a typed VfsSnapshotV1 `vfs` payload alongside the markdown, so the
mothership can diff it into append-only baseline/delta messages. Generate the TS
contract mirror from the Go-owned JSON schema (sync-vfs-snapshot-contract) and
sort connector types so diffs stay byte-stable.

* fix(lint): fix lint

* fix(vfs): forward the typed snapshot through the branch payload builder

The branch buildPayload implementations hand-list the params they pass to
buildCopilotRequestPayload and forwarded workspaceContext but dropped vfs, so the
typed snapshot never reached the Go request (req.Vfs was always nil and the
append-only delta path never engaged). Forward vfs in both the workflow and
workspace branches, and add a regression guard asserting the branch threads it
through (the bug slipped past tests because post.test mocked the payload builder
and payload.test called it directly, bypassing the branch).

* improvement(contracts): update vfs contracts

scripts/generate-mship-contracts.ts

@@ -23,6 +23,7 @@ const GENERATORS = [
   'scripts/sync-trace-attribute-values-contract.ts',
   'scripts/sync-trace-events-contract.ts',
   'scripts/sync-metrics-contract.ts',
+  'scripts/sync-vfs-snapshot-contract.ts',
 ]
 
 // Generated files under this path. We biome-format this whole dir on

scripts/sync-vfs-snapshot-contract.ts

@@ -0,0 +1,46 @@
+import { mkdir, readFile, writeFile } from 'node:fs/promises'
+import { dirname, resolve } from 'node:path'
+import { fileURLToPath } from 'node:url'
+import { compile } from 'json-schema-to-typescript'
+import { formatGeneratedSource } from './format-generated-source'
+
+const SCRIPT_DIR = dirname(fileURLToPath(import.meta.url))
+const ROOT = resolve(SCRIPT_DIR, '..')
+// Matches the sibling sync scripts' canonical layout. In a repo where the Go
+// service lives at `mothership/copilot`, pass `--input=` (e.g.
+// `--input=../mothership/copilot/contracts/vfs-snapshot-v1.schema.json`).
+const DEFAULT_CONTRACT_PATH = resolve(
+  ROOT,
+  '../copilot/copilot/contracts/vfs-snapshot-v1.schema.json'
+)
+const OUTPUT_PATH = resolve(ROOT, 'apps/sim/lib/copilot/generated/vfs-snapshot-v1.ts')
+
+async function main() {
+  const checkOnly = process.argv.includes('--check')
+  const inputPathArg = process.argv.find((arg) => arg.startsWith('--input='))
+  const inputPath = inputPathArg
+    ? resolve(ROOT, inputPathArg.slice('--input='.length))
+    : DEFAULT_CONTRACT_PATH
+
+  const raw = await readFile(inputPath, 'utf8')
+  const schema = JSON.parse(raw)
+  const types = await compile(schema, 'VfsSnapshotV1', {
+    bannerComment: '// AUTO-GENERATED FILE. DO NOT EDIT.\n//',
+    unreachableDefinitions: true,
+    additionalProperties: false,
+  })
+  const rendered = formatGeneratedSource(types, OUTPUT_PATH, ROOT)
+
+  if (checkOnly) {
+    const existing = await readFile(OUTPUT_PATH, 'utf8').catch(() => null)
+    if (existing !== rendered) {
+      throw new Error('Generated vfs snapshot contract is stale. Run: bun run mship:generate')
+    }
+    return
+  }
+
+  await mkdir(dirname(OUTPUT_PATH), { recursive: true })
+  await writeFile(OUTPUT_PATH, rendered, 'utf8')
+}
+
+await main()