feat(release): scaffold v2 parser package (annotate-based pipeline)

New package alfred/domain/release/parser/ lays the foundation for the
release parser refactor (specs in memory). Exposes:

- Token: frozen VO carrying text + stream index + TokenRole + extra dict.
  with_role() returns a new instance (no mutation).
- TokenRole: str-backed enum split into structural (TITLE/YEAR/SEASON_EP/
  GROUP), technical (RESOLUTION/SOURCE/CODEC/AUDIO_*/BIT_DEPTH/HDR/
  EDITION/LANGUAGE), and meta (SITE_TAG/UNKNOWN) families.
- pipeline.strip_site_tag(): pulls a [site.tag] prefix or suffix.
- pipeline.tokenize(): release name -> list[Token] (all UNKNOWN),
  string-ops split on kb.separators (no regex, per CLAUDE.md).
- pipeline.annotate(): documented stub. Walk order recorded in docstring
  (group right-to-left, then season/episode, year, tech, title).

Legacy parse_release in release.services remains the live implementation
until the annotate step lands. Scaffolding tests verify Token API,
site-tag stripping (prefix/suffix), and tokenize output shape.

Refs: project_release_parser_v2_specs (memory)

tests/domain/release/test_parser_v2_scaffolding.py

@@ -0,0 +1,79 @@
+"""Scaffolding tests for the v2 parser package.
+
+These tests lock the **shape** of the new pipeline (token VOs, tokenize
+output, site-tag stripping) before the annotate step is wired in. They
+do not check parsed-release output yet — that comes once :func:`annotate`
+is implemented and the fixtures-based suite switches over.
+"""
+
+from __future__ import annotations
+
+from alfred.domain.release.parser import Token, TokenRole
+from alfred.domain.release.parser.pipeline import strip_site_tag, tokenize
+from alfred.infrastructure.knowledge.release_kb import YamlReleaseKnowledge
+
+_KB = YamlReleaseKnowledge()
+
+
+class TestToken:
+    def test_default_role_is_unknown(self) -> None:
+        t = Token(text="1080p", index=3)
+        assert t.role is TokenRole.UNKNOWN
+        assert not t.is_annotated
+
+    def test_with_role_returns_new_instance(self) -> None:
+        t = Token(text="1080p", index=3)
+        promoted = t.with_role(TokenRole.RESOLUTION)
+        assert promoted is not t
+        assert promoted.role is TokenRole.RESOLUTION
+        assert t.role is TokenRole.UNKNOWN  # original unchanged (frozen)
+
+    def test_with_role_merges_extra(self) -> None:
+        t = Token(text="x265-KONTRAST", index=5)
+        promoted = t.with_role(TokenRole.CODEC, group="KONTRAST")
+        assert promoted.role is TokenRole.CODEC
+        assert promoted.extra == {"group": "KONTRAST"}
+
+
+class TestStripSiteTag:
+    def test_no_tag(self) -> None:
+        clean, tag = strip_site_tag("The.Movie.2020.1080p-GRP")
+        assert tag is None
+        assert clean == "The.Movie.2020.1080p-GRP"
+
+    def test_suffix_tag(self) -> None:
+        clean, tag = strip_site_tag("Sinners.2025.1080p-[YTS.MX]")
+        assert tag == "YTS.MX"
+        assert clean == "Sinners.2025.1080p-"
+
+    def test_prefix_tag(self) -> None:
+        clean, tag = strip_site_tag("[ OxTorrent.vc ] The.Title.S01E01")
+        assert tag == "OxTorrent.vc"
+        assert clean == "The.Title.S01E01"
+
+
+class TestTokenize:
+    def test_simple_release(self) -> None:
+        tokens, tag = tokenize("Back.in.Action.2025.1080p.WEBRip.x265-KONTRAST", _KB)
+        assert tag is None
+        texts = [t.text for t in tokens]
+        # Dash is not a separator, so x265-KONTRAST stays glued.
+        assert texts == [
+            "Back", "in", "Action", "2025", "1080p", "WEBRip", "x265-KONTRAST",
+        ]
+
+    def test_all_tokens_start_unknown(self) -> None:
+        tokens, _ = tokenize("Back.in.Action.2025.1080p.WEBRip.x265-KONTRAST", _KB)
+        assert all(t.role is TokenRole.UNKNOWN for t in tokens)
+
+    def test_indexes_are_contiguous(self) -> None:
+        tokens, _ = tokenize("A.B.C.D", _KB)
+        assert [t.index for t in tokens] == [0, 1, 2, 3]
+
+    def test_strips_site_tag_before_tokenize(self) -> None:
+        tokens, tag = tokenize(
+            "Sinners.2025.1080p.WEBRip.x265.10bit.AAC5.1-[YTS.MX]", _KB
+        )
+        assert tag == "YTS.MX"
+        # Site tag substring must not appear among tokens.
+        assert not any("YTS" in t.text for t in tokens)