feat: deep-link timeline export (dayflow://export-timeline)

[DucretJe]

feat: Deep-link timeline export (dayflow://export-timeline)

Note

I'm not used to swift apps, this code change is mainly done using AI. I tested it, it seems to be good, my main concern is about the path you pass to the .md artifact. basically we just allow it to drop it in allowed paths, maybe we could not give choice and send it to Downloads.

Closes #178.

What

Adds a non-interactive deep-link action that exports the Dayflow timeline to a Markdown file, so it can be triggered from Raycast, Alfred, Apple Shortcuts, or cron — closing the gap in #178 (today the Markdown export is only reachable through Settings, which opens an interactive NSSavePanel, while recording start/stop is already automatable via deep links).

# Export today to ~/Downloads
open "dayflow://export-timeline?date=today"

# Export a date range to a specific file
open "dayflow://export-timeline?start=2026-06-01&end=2026-06-07&path=~/Documents/last-week.md"

# Export yesterday into a folder and reveal it in Finder
open "dayflow://export-timeline?date=yesterday&path=~/Documents/reports/&reveal=true"

Parameters (query keys, case-insensitive):

Parameter	Values	Default
date	today, yesterday, or YYYY-MM-DD (single day)	today
start / end	same grammar (inclusive range)	—
path (aliases to, destination)	a file path or a directory to write into; ~ expanded	~/Downloads/Dayflow timeline <range>.md
reveal	true / 1 / yes → reveal in Finder when done	false

How

• TimelineRangeExport (new) — the shared builder that turns a day range into Markdown + counts. Both the Settings UI export and the new deep link call it, so they produce identical output from one source of truth (it also now owns the shared defaultFileName).
• TimelineExportRequest (new) — a pure, fully unit-tested URL→parameters parser (no file or DB I/O). Returns a Result with typed errors.
• TimelineExportService (new) — the side effects: resolve the destination, write the file, emit analytics, optionally reveal in Finder.
• AppDeepLinkRouter — adds the export-timeline action (alias export) next to the existing start-recording/stop-recording/referral actions.
• OtherSettingsViewModel — refactored to call the shared builder (its inline day loop is gone).
• Reuses the existing TimelineClipboardFormatter.makeMarkdown and timelineDisplayDate (4am→4am timeline day). No project.pbxproj edits needed — the project uses file-system-synchronized groups.

Security

The dayflow:// scheme is invokable by any local app or webpage, and the app is not sandboxed. To prevent a hostile link from overwriting arbitrary files (~/.zshrc, ~/.ssh/config, LaunchAgents) or exfiltrating the timeline:

• Deep-link exports are constrained to the user's Downloads, Documents, and Desktop folders (and subfolders). .. is collapsed before the containment check; out-of-bounds paths are rejected and nothing is written.
• The export range is capped at 366 days per call, so one link can't trigger thousands of background DB reads.
• The export runs on a background GCD queue (off the Swift cooperative thread pool) and fails soft (logged + a timeline_export_failed analytics event), never crashing.

The interactive Settings export is unchanged and still uses NSSavePanel.

Tests

Build and Unit tests are passing.
No idea how to do the integration tests :/