Move note title and URL from separate inputs into the note body (UI only) #83

Summary

Follow-up to #75 (tags moved into the note body, PR #82). Move title and URL entry for notes from dedicated inputs into the note document itself, using smarter semantics: the first line is the title (no prefix), and an optional url: line declares the URL. UI only: no changes to the backend, tasks, Home view, or shared-note views. The payload contract ({ title, description, url, tags } on POST /rest/notes / PATCH /rest/notes/{id}) is unchanged — the client derives title and url from the document.

Scope: client/src/views/NoteAdd/index.tsx (plus i18n strings and tests).

Current state (findings)

• Note add/edit lives in client/src/views/NoteAdd/index.tsx (single component, add + edit modes).
• Tags already live in the body as a strict footer line tags: a, b (last non-empty line, case-insensitive), parsed per keystroke, stripped from description on save, re-synthesized on load (feat: move tags to note document. Issue 75 #82): TAGS_FOOTER_PATTERN, parseTagsFooter, stripTagsFooter, synthesizeTagsFooter.
• Title input: FormInput at index.tsx:500-513 (required, name="note_title"). URL input: FormInput at index.tsx:517-530 (name="url"). Neither has max-length or format validation client-side; the backend validates title size.
• Save guard at index.tsx:317-320 blocks save when title or content is blank ("Please fill in all the fields").
• Form card header: Card.Title at index.tsx:468 renders i18n note_form_title ("Add note"). Page hero (ContentHeader, index.tsx:456-462) stays static.
• Helper text below the textarea (index.tsx:610-612, hardcoded English): "Add a final line `tags: a, b` to tag this note."
• Markdown preview (ModalMarkdown) already receives the body with the tags footer stripped.
• Draft autosave to localStorage stores { title, content, noteUrl } under draft:note:new / draft:note:edit:{id} (debounced 1.5s).
• i18n via react-i18next; strings in client/src/constants/{english,spanish,portuguese,russian}.ts.
• Tests: client/src/__test__/views/NoteAdd.test.tsx (Vitest + testing-library).

Design decisions (grilled and settled)

Model

• Line 1 of the document is the title. No prefix. Even a long paragraph on line 1 is the title; if it exceeds the backend's title size limit, the backend rejects it and the user must shorten it (existing error surfacing via AlertError).
• URL is declared on a line matching /^url:\s*(.*)$/i, positioned after line 1 and before the tags: footer line.

Parse rules

• Title normalization: strip leading markdown heading markers (#+space sequences) and trim, both for the stored title and the live header display. # My Title → My Title.
• Blank first line blocks save: strictly line 1, no "first non-empty line" fallback. Shows the existing "Please fill in all the fields" error.
• URL line: case-insensitive prefix; if multiple url: lines exist, the first wins and the rest stay as body text. The value is the first token after the prefix — split on any delimiter (whitespace, comma, etc.), so url: https://a https://b → https://a. No URL format validation (backend owns validation). Empty url: → no URL.

Save

• Title and URL are stripped from description before saving (same as the tags footer), so they never leak into Home previews, the public shared-note page, markdown rendering, or search. title and url go in their dedicated payload fields.

Load (edit mode)

• Re-synthesize the document as: title on line 1, url: <url> on line 2 (deterministic position, only when a URL exists), then the body, then the tags footer.
• Existing draft-restore behavior is preserved: a stored draft body wins over synthesis.

Live UI

• Remove the Title and URL FormInputs entirely (and their state).
• Live card title: the Card.Title reflects the normalized line 1 per keystroke, reinforcing that line 1 is the title. Fallback when line 1 is blank: "Untitled note" (new i18n key added to all 4 locale files). The static page hero (ContentHeader) is unchanged.
• Helper text updated to: "The first line is the note title. To link a URL to this note, add a line `url: ` before the tags. Add a final line `tags: a, b` to tag this note."

Markdown preview

• ModalMarkdown renders the body with the title line, url: line, and tags footer all stripped.

Drafts

• Draft now stores content only (title/URL derive from it).
• Old-shaped drafts (with separate title/noteUrl keys) are merged into the content once on load, then treated as new-shaped.

Acceptance criteria

• First line of the document is sent as title (leading #s stripped, trimmed); it is stripped from description on save.
• Blank first line blocks save with the existing "Please fill in all the fields" error.
• A line url: <url> between line 1 and the tags footer is parsed case-insensitively and sent as url; first url: line wins; value stops at the first whitespace/comma delimiter; the line is stripped from description on save.
• Edit mode on a legacy note (title/url only in fields) shows title on line 1 and url: on line 2; saving round-trips the same title, URL, body, and tags.
• Title and URL inputs fully removed from NoteAdd.
• Card.Title updates live per keystroke with the normalized line 1; blank line 1 shows "Untitled note"; new i18n key present in all 4 locales.
• Helper text mentions the title line, the url: line, and the tags footer.
• Markdown preview hides title, url:, and tags lines.
• Draft autosave/restore works with content-only drafts; old-shaped drafts migrate (title/url merged into content once).
• Existing tag-footer behavior (parsing, autocomplete, chips) unaffected.
• NoteAdd.test.tsx updated for all of the above; bash tools/check-frontend.sh passes.