Adopt "Title (YYYY)" pool naming and clean Filmotéka link names

PROJECT.md

@@ -98,8 +98,17 @@ movie table, and one-click Filmotéka generation.
   Filmotéka output, with the files materialized as **hardlinks** into the pool.
   So `pool/Seriály/...` is cloned 1:1 into `output/Seriály/...` (same structure,
   hardlinked files). This is how Seriály work.
-- **File naming:** imported movies are renamed to **`Title.ext`** (no year in the
-  filename; year lives in metadata/tags).
+- **File naming:** pooled movies follow the convention **`Title (YYYY).ext`** — a
+  clean title plus a four-digit year in parentheses (`naming.py`:
+  `canonical_pool_stem` / `parse_pool_stem`). The year lets two same-named films
+  coexist and makes the filename self-describing (`File.name_context` recovers
+  the year from the filename when no ČSFD/tag year is present). The GUI **import
+  requires a four-digit year** (per-row *Rok* field, pre-filled from the source
+  filename and fillable from ČSFD — a ČSFD-suggested year is tinted blue to be
+  verified, a name colliding with the pool is tinted red). *Filmy → "Přejmenovat
+  dle ČSFD (rok)…"* (`FileManager.rename_all_to_canonical`) brings older
+  `Title.ext` files up to the convention from their ČSFD metadata; files without
+  a known year are skipped. `File.title` always stays the clean title (no year).
 - **Import copy vs move:** by default the original file is **copied** into the
   pool (non-destructive); the import dialog also offers a **move** option that
   relocates the source into the pool instead.
@@ -122,11 +131,20 @@ movie table, and one-click Filmotéka generation.
   The `transform` (e.g. `decade_band`) shapes only the **folder name** — tags keep
   the **exact value** (rating → tag `Hodnocení/90`, folder `Dle hodnocení/90–100 %`);
   it is applied at Filmotéka generation via `filmoteka_category_transforms`.
-- **Per-category filename template** (`filename_template` in a schema entry): the
-  hardlink name **inside that category's folders only** is rendered from the
-  movie's metadata (`File.name_context`: title/year/rating/ext/stem/filename plus
-  any free-form attributes), e.g. a Kolekce with `"{collection_sort} - {title}{ext}"`.
-  Other folders and the pool file keep the plain name; applied via
+- **Filmotéka link naming (clean title, year on collision):** the default
+  hardlink name in the tag tree is the movie's **clean title** — `Title.ext`,
+  *not* the pooled `Title (YYYY).ext`. When two different films would collide on
+  that name **within one folder**, the colliding ones keep the disambiguating
+  **year** (`Title (YYYY).ext`); a residual same-title-and-year clash gets a
+  stable numeric suffix. `HardlinkManager._plan_links` resolves the whole tag
+  tree to a collision-free `(file, path)` plan that **both** link creation and
+  obsolete-detection consume, so they can never disagree on a name (the previous
+  churn source). Copy-as-is mirrors (Seriály) are unaffected — they mirror 1:1.
+- **Per-category filename template** (`filename_template` in a schema entry):
+  overrides the default naming **inside that category's folders only**, rendered
+  from the movie's metadata (`File.name_context`: title/year/rating/ext/stem/
+  filename plus any free-form attributes), e.g. a Kolekce with
+  `"{collection_sort} - {title}{ext}"`. Applied via
   `filmoteka_category_filename_templates`.
 - **Free-form per-movie attributes** (`File.attributes`, set in the GUI): arbitrary
   `key → value` metadata stored in the index and merged into `name_context`, so
@@ -152,6 +170,9 @@ movie table, and one-click Filmotéka generation.
 
 ## Done
 
+- Pool naming convention `Title (YYYY).ext` (`naming.py`): year required at
+  import (per-row Rok field, blue = ČSFD-suggested, red = pool collision), plus
+  "Přejmenovat dle ČSFD (rok)" to bring older files up to the convention
 - Video integrity check (`integrity.py`, Testy → "Kontrola integrity videa"):
   FFmpeg-based scan for corrupted/unreadable video data, deep (full decode) or
   quick (ffprobe), over selected movies or the whole pool