v2 Phase 2 — Template-first transition (SQLite library, sequence + date widgets, gallery home)

[szrudi]

Umbrella issue for Phase 2 of the v2 UI overhaul — the speculative half. Phase 1 (#28) stands on its own regardless of whether Phase 2 happens; Phase 2 explores whether a more template-first experience is right for this project's actual usage. The maintainer's own use is closer to one-off labels, so the homepage flip in slice 2.5 specifically is genuinely uncertain and open to reshaping based on input from labelle-org and other users.

Within Phase 2, slices 2.1–2.4 (server-saved templates, gallery as a route, sequence + date widgets) are useful features even without the homepage flip. Only 2.5 is the speculative big swing.

Builds on Phase 1 (#28) and reuses the Sheet primitive + stacked-row UI from slices 1.2 / 1.3.

Slices

2.1 — Save labels to server, SQLite-backed (M)

• GET/POST/DELETE /api/templates, GET /api/templates/:id.
• Storage: SQLite (templates.db alongside the existing LABELLE_STATE_FILE directory). sqlite3 is stdlib — no new dep.
• Schema (v1):

  templates(
    id TEXT PRIMARY KEY,           -- uuid
    name TEXT NOT NULL,
    description TEXT,
    body_json TEXT NOT NULL,       -- v2 label JSON, reuses labelFile.ts format
    favorite INTEGER NOT NULL DEFAULT 0,
    created_at INTEGER NOT NULL,
    updated_at INTEGER NOT NULL,
    last_printed_at INTEGER
  )
  

• Wrap CRUD in a tiny server/templates_store.py mirroring the shape of printer_settings.py. First call creates the table; future schema bumps use PRAGMA user_version + additive migrations.
• Add "Save to library" alongside the existing "Save to file" in SaveLoadButtons — not a replacement.
• Done when: user saves the current label as a named template, refreshes the page, fetches it back via API.

2.2 — Template gallery as a route (M)

• Add lightweight client-side routing (React Router recommended for shareable template URLs).
• / = current designer (unchanged for now), /templates = gallery with server-rendered thumbnails.
• Tap → load into the designer (/?template=:id).
• Mobile tab bar / desktop top nav.
• Done when: visiting /templates shows template thumbnails; tap loads into the designer.

2.3 — New widget: Sequence number (M)

• SequenceWidget with start, step, padding (e.g. 04d → 0001), prefix, suffix.
• Single-print mode: current value. Batch mode: increments per output label.
• Establishes the "resolved-at-print-time" pattern that 2.4 reuses.
• Open decision: if a batch is cancelled mid-run, does the sequence resume or restart from start? Default: restart from start, documented.
• Done when: template with one sequence widget prints Asset-0001…Asset-0050 on 50 sequential labels.

2.4 — New widget: Date stamp (S)

• DateWidget with format (ISO, dd-mm-yyyy, etc.) and offsetDays (e.g. "today + 90" for expiry).
• Resolved server-side at print time. Editor previews "as printed today".
• Done when: label with Date(today+30, dd-mm-yyyy) prints today's date plus 30 days.

2.5 — Template-first home + variable fill view (L, most speculative slice)

May not happen as described. An alternative shape is to keep the designer at / and surface templates prominently from there. Direction here will be reshaped based on feedback before commitment.

• / would render the gallery; designer moves to /design.
• "New blank label" on the gallery for from-scratch users.
• Templates with variables → a "fill" sheet (reuses 1.2 sheet primitive + 1.3 stacked-row UI) → print without entering designer.
• "Edit template" affordance for tweaks.
• URLs: /t/:id (fill), /t/:id/edit (designer-with-template-loaded).
• If we go this way, this PR is the v2.0.0 cutover. Major bump.
• Done when (if pursued): first-time mobile user lands on /, taps a name-badge template, fills "Alice", and prints — never seeing the widget list.

Phase exit criteria

Two possible outcomes depending on how the template-first thesis lands:

1. If 2.5 is pursued as described: fresh browser on a phone → land on / → see template gallery → tap a template → fill values → print.
2. If 2.5 is reshaped: 2.1–2.4 still ship as standalone features; templates live alongside the designer rather than replacing it.