ADR-0019 §9 sweep (3/3): ui.rs prose strings (caught in manual sanity)

Surprise gap from the post-sweep sanity check — `ui.rs` had a
substantial set of TUI-rendered strings that the previous two
sweep passes didn't cover. Caught by grepping for capitalised
literals in `ui.rs` after running the binary smoke check.

## Migrated

- **modal.*** — load picker title / empty state / path
  prompt; rebuild confirm title / "Continue?" prompt.
  (modal.path_entry's title comes from `save.*` since it's
  the save / save-as dialog.)
- **save.*** — `save` no-op hint, modal titles for
  Save / Save as, modal prompt body.
- **status.*** — status bar `Project:` label and the
  `(no project)` placeholder.
- **panel.*** — `Tables` panel title, `(none yet)`
  placeholder for empty tables, `(no active hint)`
  placeholder for the hint panel.
- **shortcut.*** — the bottom-bar keyboard hint labels
  (submit, confirm, cancel, yes, no, load, select,
  browse_path, back_to_list, switch, advanced_once,
  cancel_one_shot, quit). Each is a translatable label
  paired with a key name (Enter / Esc / Ctrl-C / etc.) at
  the call site. Keystroke names are deliberately left as
  literals — translating them would mean retraining users
  away from what their keyboard says.

The `push_shortcut` closure's parameter type changed from
`&'static str` to `&str` so it accepts the catalog-returned
String.

## Deliberately left

- **Echo prefix tags**: `[simple] `, `[advanced] `,
  `[system] `, `[error]  `. Their column widths are
  hardcoded into the wrap-width calculation in
  `render_output_panel`; translating them would silently
  break alignment. Worth a follow-up pass if a future locale
  needs different prefixes (would need `mode.label()` and
  the echo-tag widths to live behind a single locale-aware
  function).
- **Mode labels**: `SIMPLE` / `ADVANCED` / `Advanced:`
  rendered in the input panel border. Same alignment
  reasoning as the echo tags — also they're keywords (the
  user types `mode simple` to switch), so translating the
  display label without translating the command word would
  be confusing. Left as is.
- **Visual decoration**: `[Y]`, `[N]`, `[TEMP] `, `>`
  cursor markers, `█` cursor block, `↑↓` arrow glyph,
  `›` selection marker. Universal symbols / labels rather
  than translatable prose.

## Catalog totals

The catalog now has ~170 entries across 16 categories.
`tests/engine_vocabulary_audit` passes — no engine
vocabulary leaks anywhere user-reachable.

## Tally

610 tests passing (no change — pure refactor with
identical-output catalog substitutions). Clippy clean
with nursery lints. Release builds at 7.8 MB.

ADR-0019 §9 is now genuinely complete.

src/friendly/strings/en-US.yaml

@@ -309,6 +309,48 @@ modal:
   path_entry_empty_name: "path entry: empty name"
   path_entry_empty_path: "path entry: empty path"
   load_picker_nothing: "nothing to load"
+  # Modal titles + body prose rendered by ui.rs.
+  load_picker_title: "Load project"
+  load_picker_empty: "(no projects in data directory)"
+  load_picker_path_prompt: "Path to project directory:"
+  rebuild_confirm_title: "Rebuild project"
+  rebuild_confirm_prompt: "Continue?"
+
+# ---- Save / save-as command surfaces ---------------------------------
+save:
+  # `save` on a named project is a no-op with a friendly hint.
+  already_saved: "already auto-saved; use `save as` to copy to a different location"
+  # Modal titles for `save` (on a temp) vs `save as`.
+  title_as: "Save as"
+  title_save: "Save"
+  # Prompt body for the path-entry modal opened by save / save as.
+  path_prompt: "Name (under data dir/projects) or absolute path:"
+
+# ---- Status bar (project label) and panels ---------------------------
+status:
+  no_project: "(no project)"
+  project_label: "Project: "
+
+panel:
+  tables_title: "Tables"
+  tables_empty: "(none yet)"
+  hint_empty: "(no active hint)"
+
+# ---- Shortcut hints (paired with key names in the bottom bar) -------
+shortcut:
+  submit: "submit"
+  confirm: "confirm"
+  cancel: "cancel"
+  yes: "yes"
+  no: "no"
+  load: "load"
+  select: "select"
+  browse_path: "browse path"
+  back_to_list: "back to list"
+  switch: "switch"
+  advanced_once: "advanced once"
+  cancel_one_shot: "cancel one-shot"
+  quit: "quit"
 
 # ---- mode / messages banners (app-level commands) -------------------
 mode: