fix(client): address PR #109 review — 6 warnings + 5 suggestions

Star map (W1-W3, S3):
- _process visibility guard + dirty flag (no redraw when hidden/unchanged)
- _system_hash masked to 31-bit positive range
- Extracted _find_nearest_system() shared helper

game_state.gd (W4):
- Inline load() in apply_snapshot() replaces per-tick overhead; safe at
  runtime because script is already in resource cache

Data pipeline (W5-W6):
- Script-relative path resolution via __file__
- --check mode + make check-star-map staleness target

Minor (S1-S2, S5):
- Removed redundant bone_idx assignment
- Simplified double-negative test assertion
- Documented autoload parse-order convention in CLAUDE.md

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CLAUDE.md

@@ -84,6 +84,16 @@ The ticketing database (`settledreach.db`) lives in the **parent directory** sha
 - Three test tiers: (1) Live server — highest fidelity, (2) MessagePack replay via `Protocol.decode_snapshot()` — for unreachable rooms, (3) TestHarness mock — for UI-only tests where fog data doesn't matter.
 - `make fixtures-gauntlet` regenerates real server snapshot fixtures from the Gauntlet world.
 
+### GDScript conventions
+
+**Autoload parse-order rule:** Autoload scripts (`client/scripts/autoloads/`) compile before global `class_name` scripts are registered. Referencing a `class_name` type directly in an autoload causes a parse-time "not declared" error. Pattern:
+- Declare fields untyped: `var my_field = null` (comment the intended type)
+- Do **not** reference `class_name` types at the top level or in `_ready()` of autoloads
+- In method bodies called at runtime (e.g. `apply_snapshot`), use `load()` inline — by then the script is cached and `load()` returns the cached resource without reloading: `var CVD := load("res://scripts/rendering/character_visual_descriptor.gd")`
+- Do **not** cache the `load()` result in `_ready()` — `_ready()` fires during autoload init, before the target script is in the resource cache, causing an actual file reload that breaks self-references in scripts using their own `class_name`
+
+`game_state.gd` (`character_visual_descriptor` field) and `sim_bridge.gd` (`harness` field) follow this pattern.
+
 ### File conventions
 - Decisions: domain files in `decisions/` (see `decisions/README.md` for index)
 - Decision IDs: `D-NNN` (confirmed), `Q-NNN` (open questions), `R-NNN` (rejected)