feat: multimodal attachments — file→text, transcription, native image/audio/video (+ CLI @path//attach)

[localai-bot]

What

End-to-end multimodal attachments for nib: attach images/audio/video and documents to a chat. The app inspects the active model's capabilities and routes each file — native content part to a capable model, transcription (parakeet) for audio a text-only model can't hear, or document→text conversion — then sends one turn.

Reachable today from the CLI and TUI:

• @path inline — > summarize @report.pdf (resolve-if-exists: only real files attach; prose @mentions stay literal).
• /attach — stage files across turns; /attach --transcribe|-t <audio> forces transcription; /attach lists, /attach clear resets.

How it's layered

Core (pure-Go, no cgo/binaries):

• extraction/ — file→text: PDF via go-pdfium+wazero (WASM), DOCX/XLSX/PPTX/EPUB via stdlib, plus a plain-text reader.
• specialist/ — LocalAI delegation: Transcribe (→ /audio/transcriptions, parakeet/whisper) and Describe (vision) + DataURI; models auto-selected by usecase.
• attachments/ — Sniff + Route decision table, a fail-safe FetchCapabilities client (LocalAI's /v1/models/capabilities), and the Apply orchestrator producing Result{Parts, TextPreamble, Blocked}.

Wiring:

• chat.ContentPart implements cogito's TypedMultimedia (image/audio/video); SendMessage(text, parts...) widened; SendWithAttachments(ctx, text, files, overrides) resolves capabilities, converts/transcribes, and sends one multimodal turn, returning blocked files.
• slash parses @path + /attach; a shared attachstage.BuildSend combines staged + inline files and the transcribe-override map; the CLI REPL and TUI both wire it and surface blocked as notices, clearing staging on success only.

Depends on cogito's native content-part support (mudler/cogito#63, merged) — bumped here.

Routing (capability-aware)

Attached	Active model	Treatment
Image	vision	native image_url
Image	text-only	blocked (switch models)
Audio	audio-capable	native input_audio (or -t → transcribe)
Audio	text-only	transcribe (parakeet)
Video	video-capable	native video_url
Document / text	any	converted to text

Testing

Every pure seam is unit-tested: extraction (per-format fixtures), specialist (httptest wire assertions), attachments (full Route table, Apply incl. block + fail-fast), parseAtPaths/Resolve, attachstage.BuildSend, buildUserFragment, composeAttachments. go build ./... + package suites green.

Built subagent-driven with per-task spec+quality reviews and two whole-branch reviews. The final review caught and this PR fixes: native audio was shipping an empty input_audio.format (now carried from the file extension), and a queued @path message injected mid-run dropped its attachments (now held for end-of-run). The TUI interactive path was verified by code-reading; a manual smoke against a live LocalAI is the recommended pre-merge check.

Follow-ups (not in this PR)

Builtin agent tools (read_image/transcribe_audio/read_video — visionModel config is wired ahead for these), and the desktop (Dante) attachment UI.

🤖 Generated with Claude Code