feat(notifications): capture service-worker push notifications for slack (t067)

[nguyenthienthanh]

Stacked on #4 (t066). Merge #4 first — until then this PR's diff also shows the t066 commit. After #4 merges, this reduces to just the t067 changes.

Problem

The page hook (window.Notification, slack-notify.js) only sees notifications Slack fires from the page realm. Slack also delivers many notifications from its service worker's push handler via registration.showNotification(...) — a separate JS realm the page script can't reach. Those were silently missed (called out as out-of-scope in t064/t066).

Changes

• reconcile now also matches service_worker targets whose adapter declares a swScript (Slack), and attaches a read-only side-channel to them.
• The SW channel injects inject/slack-sw-notify.js via Runtime.evaluate — a worker has no Page domain, so there's no document-start hook and no t066 keep-alive. The script patches ServiceWorkerRegistration.prototype.showNotification and ships the same __cdpNotify toasts the page path uses.
• The single Slack SW serves every workspace (origin-level), so its URL carries no team id. The worker script derives the per-workspace groupKey from the notification payload (defensive probe; logs one sample to the worker console for HITL tightening).

Known limitation (documented, not fixed here)

A worker that spins up fresh on a push and fires showNotification before the next 5s reconcile attaches is missed — there's no SW-start barrier. A hardened version would use a browser-level CDP session with Target.setAutoAttach({ waitForDebuggerOnStart: true }) to attach + inject before the worker runs. The t066 page keep-alive keeps the registration warm enough to stay listed across reconciles in the common case. See docs/tasks/067.

Tests

• pnpm test — 635 passing (6 new: SW attach / no-Page-domain / no-keep-alive / ingest+groupKey / drop-on-vanish / page+SW coexist).
• pnpm typecheck, Biome (changed files) — clean.
• Needs HITL: the Slack SW push payload shape is a defensive guess — verify against a live push and tighten the team/channel probes using the one-time [cdp-sw-notify] sample options: console log.

🤖 Generated with Claude Code

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Also in this PR — clipboard file paste (video/doc)

Bundled at the author's request (one PR on this branch). Independent of the t067 SW work.

Problem: pasting a copied file (e.g. a video from Finder) pasted the file's icon thumbnail, not the file. Root cause: the paste path assumed clipboard image bits, never a file reference — clipboard.readImage() returns a copied file's Quick Look icon (non-empty), so that branch won and pasteImage shipped the icon PNG; on web the native paste handler filtered items to image/ only, dropping video/*.

Changes:

• core/clipboard.js: pure mimeForName (extension → MIME); converted to CommonJS so the CJS main process can require it (aligns with the rest of core/).
• main.js: new cdp:read-clipboard-files IPC reads the real file via the clipboard's public.file-url → { name, type, dataUrl } (150 MB cap, main-process fs, no CORS wall).
• remote-page.ts: generalize pasteImage → pasteFile(dataUrl, name, type) preserving the real name + MIME; pasteImage is now a thin wrapper.
• app.tsx: Cmd+V tries files → image bits → text; web paste accepts any file kind off the native paste event.
• preload.js / vite-env.d.ts / cdp-web-transport.ts: wire/stub readClipboardFiles.

Not covered: file-picker <input type=file> upload remains the separate known limitation (needs DOM.setFileInputFiles over CDP).

Tests: pnpm test 634 → still green (2 new: mimeForName, pasteFile); pnpm typecheck + Biome (changed) clean.

Update — drag-and-drop files, streamed in chunks (commit c4876e8)

Dropping a copied video already attached the file but froze CDP. Root cause: dropFiles/pasteFile embedded the whole base64 payload in a single Runtime.evaluate, so a 62 MB video became an ~86 MB source literal the remote renderer parsed in one tick — stalling the screencast that shares the CDP socket.

• Chunked transfer (load-bearing): streamFiles pushes the base64 to the remote in ~2 MB chunks (window.__cdpFiles[key]); assembleFilesExpr joins + decodes into a real File then dispatches. pasteFile/pasteImage/dropFiles are now async.
• dropFiles(specs, clientX, clientY) seam: maps the drop point through the Input-Forwarding coord resolver and synthesizes dragenter/dragover/drop DragEvents carrying the files in a DataTransfer on the element under the cursor.
• viewport.tsx: drag-target overlay + progress toast; reads dropped Files via FileReader (Electron + web); 100 MB/file cap (toasted when skipped); a window-level guard preventDefaults stray file drags so they can't navigate the Electron window to file://.
• Clipboard paste of a file stays OS-dependent (a copied video may expose only an icon bitmap), so drag-drop is the reliable path.

Tests rewritten for the chunked protocol (payload rides the chunk pushes, never the final dispatch). 636 passing; typecheck + Biome (changed) clean.

[nguyenthienthanh]

@duongdev follow-up to #4. Captures Slack's service-worker push notifications (the realm the page hook can't see). Experimental — the SW push payload probe needs a quick HITL tighten against a live push (one-time console sample included).