Add per-item exclude to the rename confirmation modal

Each row in the "Confirm Rename" plan now has a small x button that drops just that
file from the batch without closing the modal or needing to cancel and re-select
beforehand (previously it was all-or-nothing - "Exclude Selected" on the file list was
the only way to leave a file out, and only before opening Rename at all). Excluding
every row disables the confirm button and shows an empty-plan hint instead of sending
an empty batch. No Rust changes needed - this is pure plan-state filtering in the
frontend, RenamePlanEntry's shape is unchanged.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

README.md

@@ -11,7 +11,8 @@ TMDB ("Fetch Data") are working for both TV episodes and movies — including fu
 title disambiguation, so a search that returns several similarly-named results doesn't
 just take TMDB's top-ranked hit — and the actual on-disk rename operation is wired up
 (skip-on-conflict, with a confirmation step showing the full old-path/new-path plan
-before anything touches disk). Rename can also organize files into subfolders —
+before anything touches disk, and a per-row ✕ to drop an individual file from that plan
+at the last step). Rename can also organize files into subfolders —
 including ones that don't exist yet — when the naming scheme includes a `/`. Every
 completed rename is logged to a history panel that can undo it, moving files back to
 their original paths. A single loaded batch can freely mix TV episodes and movies —
@@ -230,12 +231,10 @@ ported from, for anyone picking this up:
    `--conflict` variants beyond skip (auto-number, override), and the CLI flag surface
    itself.
 7. **The rest of the UI** — the Rename panel (file loading, drag-drop, live preview,
-   local matching, confirmed rename, rename history/undo) is built; the other five
-   sidebar panels (Episodes/Subtitles/SFV/Filter/List) are still stub screens, plus
-   Align up/down reordering and Presets on the Rename panel itself are still no-ops.
-   There's also no per-item exclude inside the rename confirmation modal yet (it's
-   all-or-nothing — use "Exclude Selected" on the file list beforehand to leave a file
-   out entirely).
+   local TV/movie matching, confirmed rename with per-item exclude, rename history/undo)
+   is built; the other five sidebar panels (Episodes/Subtitles/SFV/Filter/List) are
+   still stub screens, plus Align up/down reordering and Presets on the Rename panel
+   itself are still no-ops.
 8. **Undo/history for renames** — done, as a flat JSON-backed undo stack rather than a
    full port of `net.filebot.HistoryDialog`'s session/element log
    (`crates/renamr-core/src/history`, `src-tauri/src/history.rs`). Every successful