feat: pzmm conflict detection + content-type categorization

- mod_files manifest table populated at parse time
- POST /api/conflicts endpoint
- mod_types fingerprinting feeds derive_category
- DD filelist regex broadened to cover conflict-eligible exts
- media/maps/<*>/* excluded from manifest (per-mod namespaced,
  no conflict value, can be tens of MB per mod)

Plan: docs/plans/2026-05-04-pzmm-conflict-and-typing.md

init/09_mod_files.sql

@@ -0,0 +1,34 @@
+-- pzmm-conflict-typing migration (Plan: docs/plans/2026-05-04-pzmm-conflict-and-typing.md)
+--
+-- Adds:
+--   - mod_files: per-mod manifest of conflict-eligible asset files (lua/txt/xml/json/ini)
+--                with sha1 fingerprint. Used by /api/conflicts to flag rel_paths claimed
+--                by ≥2 mods with non-equal content.
+--   - mod_parsed.mod_types: ordered tag list from detect_mod_types content fingerprinting
+--                (Maps, Vehicles, Weapons, Traits, …). Consumed by derive_category.
+--   - mod_parsed.files_manifest_built: graceful-degradation flag. False until the
+--                worker has run the single-pass media/ walk that produces both the
+--                manifest rows and mod_types. Old cached rows stay false until they
+--                organically re-parse.
+--
+-- Backfill strategy: organic only — time_updated bumps trigger re-parse, which
+-- now also runs the manifest walk. /api/conflicts surfaces missing_manifests so
+-- the frontend can communicate gaps without lying.
+
+CREATE TABLE IF NOT EXISTS mod_files (
+    workshop_id  TEXT NOT NULL,
+    mod_id       TEXT NOT NULL,
+    rel_path     TEXT NOT NULL,
+    sha1         TEXT NOT NULL,
+    size_bytes   INTEGER NOT NULL DEFAULT 0,
+    PRIMARY KEY (workshop_id, mod_id, rel_path),
+    FOREIGN KEY (workshop_id, mod_id)
+        REFERENCES mod_parsed (workshop_id, mod_id) ON DELETE CASCADE
+);
+
+CREATE INDEX IF NOT EXISTS mod_files_rel_path_idx ON mod_files (rel_path);
+CREATE INDEX IF NOT EXISTS mod_files_mod_idx ON mod_files (workshop_id, mod_id);
+
+ALTER TABLE mod_parsed
+    ADD COLUMN IF NOT EXISTS mod_types            TEXT[]  NOT NULL DEFAULT '{}',
+    ADD COLUMN IF NOT EXISTS files_manifest_built BOOLEAN NOT NULL DEFAULT FALSE;