refactor: split auto-rules into modpack/ vs curated/ provenance subdirs

The previous flat data/rules/ flattened a real distinction:
  - data/rules/modpack/  mirrors of upstream modpack-author-bundled
                         sorting_rules.txt (HellDrinx). Update when
                         upstream publishes; don't unilaterally edit.
  - data/rules/curated/  sortof-operator-authored rules for individual
                         mods whose authors didn't declare load order
                         in their mod.info (RV Interior Expansion).

The loader stays provenance-agnostic; trigger values in _RULES_TRIGGERS
are paths relative to data/rules/ ("modpack/helldrinx.txt" etc.).
File headers in each rules file declare the provenance category and
edit policy.

data/rules/curated/rv_expansion.txt

@@ -1,4 +1,7 @@
-; RV Interior Expansion (B42) — sorting rules
+; RV Interior Expansion (B42) — sortof-operator-curated sorting rules.
+; Provenance: data/rules/curated/. Edit freely when authoring new
+; load-order constraints for mods whose authors didn't declare them.
+;
 ; Triggers:
 ;   - 3618427553 (RVInteriorExpansion, map folder rvupdate)
 ;   - 3622163276 (RVInteriorExpansionPart2, map folder rv2)

data/rules/modpack/helldrinx.txt

@@ -1,11 +1,11 @@
-; HellDrinx modpack — bundled sorting rules
+; HellDrinx — modpack-author-bundled sorting rules (mirror of upstream).
+; Provenance: data/rules/modpack/. Update when the modpack publishes a
+; new sorting_rules.txt; do not edit unilaterally.
+;
 ; Triggers: HellDrinx FULL (3672556207), HellDrinx LITE (3662909244).
 ; Auto-injected by app.py:_auto_rules_for() when either trigger wsid is in
 ; the user's input. User-supplied rules are appended afterward and override
 ; these on conflicting keys.
-;
-; Source: HellDrinx FULL/LITE — keep this file in sync with the modpack's
-; upstream sorting_rules.txt when it updates.
 
 [PROJECTRVInterior42]
 loadFirst=on