Adds the foundation for serving local files to the browser as live external
attachments with a stable id, so requests never carry arbitrary absolute paths.
- attachment-registry: in-memory, session-scoped registry. registerExternalAttachment
validates an absolute path, resolves symlinks, enforces the path guard, and mints
an `att_<uuid>` id; records are cleared when the session is removed.
- attachment path guard: a configurable blocklist (secret locations + /root,/etc
trees, extendable via attachmentBlockedPaths / CODEMAN_ATTACHMENT_BLOCKED_PATHS)
plus an optional, default-off workspace-confinement mode. Shares one
sensitive-path blocklist (web/sensitive-path.ts) with /api/download, which is
refactored to use the extracted module instead of an inline copy.
- terminal magic links: the session scans output for codeman://attach?path=... and
emits `attachmentRequested`; the web server registers the file and broadcasts an
`attachment:detected` SSE event. `codeman attach <path>` (CLI) prints the magic
link or POSTs directly when a session id is known.
- image watcher: detects png/pdf/docx/pptx dropped into a session's working dir and
emits `attachment:detected`.
- routes: POST /api/sessions/:id/attachments (register) and
GET /api/sessions/:id/attachments/:attachmentId/raw (serve), both re-checking the
guard before streaming.
Document previews/thumbnails and the attachment-history drawer build on this
foundation and land separately.
Verified: tsc --noEmit, lint, format, frontend-syntax, full test:ci (2846 passed),
and a server boot smoke (/api/status 200).
Aamer Akhter
f1c64994ad