backend-infra-engineer: Post v0.3.9-hotfix7 snapshot (build cleanup)

docs/internal/plans/hyrule-magic-support-plan.md

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+# Implementation Plan - Hyrule Magic & Parallel Worlds Support
+
+## Goal Description
+Add support for "doctoring" legacy Hyrule Magic (HM) ROMs and loading Parallel Worlds (PW) ROMs which use custom dungeon pointer tables.
+
+## User Review Required
+- **Plan:** Review the proposed detection and compatibility logic.
+
+## Proposed Changes
+
+### 1. Hyrule Magic Doctor (`z3ed rom-doctor`)
+- **Detection:**
+  - Detect HM header signatures (if any).
+  - Detect "Bank 00 Erasure" (already implemented in Phase 1, confirmed working on `GoT-v040.smc`).
+  - Detect Parallel Worlds by internal name or specific byte sequences.
+- **Fixes:**
+  - **Checksum Fix:** Auto-calculate and update SNES checksum.
+  - **Resize:** suggest resizing to 2MB/4MB if non-standard (e.g., 1.5MB PW ROMs).
+  - **Bank 00 Restoration:** (Optional) If Bank 00 is erased, offer to restore from a vanilla ROM.
+
+### 2. Parallel Worlds Compatibility Mode
+- **Problem:** PW uses a custom version of HM that moved dungeon pointer tables to support larger rooms/more data.
+- **Solution:**
+  - Add `Rom::IsParallelWorlds()` check.
+  - Implement `ParallelWorldsDungeonLoader` that uses the modified pointer tables.
+  - **Offsets (To Be Verified):**
+    - Vanilla Room Pointers: `0x21633` (PC)
+    - PW Room Pointers: Need to locate these. Likely in expanded space.
+
+### 3. Implementation Steps
+#### [NEW] [hm_support.cc](file:///Users/scawful/Code/yaze/src/rom/hm_support.cc)
+- Implement detection and fix logic.
+
+#### [MODIFY] [rom_doctor_commands.cc](file:///Users/scawful/Code/yaze/src/cli/handlers/tools/rom_doctor_commands.cc)
+- Integrate HM/PW checks.
+
+#### [MODIFY] [dungeon_loader.cc](file:///Users/scawful/Code/yaze/src/zelda3/dungeon/dungeon_loader.cc)
+- Add branching logic for PW ROMs to use alternate pointer tables.
+
+## Verification Plan
+- **Doctor:** Run `z3ed rom-doctor` on `GoT-v040.smc` and `PW-V1349.SMC`.
+- **Load:** Attempt to load PW dungeon rooms in `yaze` (once loader is updated).