feat(ci): tracing JSON format in CI, tick duration logging, schedule dump (#344, #346)

Tracing (#344):
- Add 'json' feature to tracing-subscriber dependency
- Emit JSON log format when CI=true or RUST_LOG_FORMAT=json is set
  (structured log ingestion in CI pipelines)
- Add tracing::debug! with tick_ms/budget_ms/over_budget fields on each
  tick for performance profiling and tier system debugging prerequisite

Schedule dump (#346):
- Add --dump-schedule CLI flag that prints bevy_ecs schedule graph and exits
  without requiring TCP bridge or world setup
- Add make debug-schedule target for CI artifact generation and diff-based
  regression detection of unintended system reordering

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

Makefile

@@ -7,7 +7,7 @@ GODOT := $(shell command -v godot4 2>/dev/null || command -v godot 2>/dev/null)
        pre-pr-server pre-pr-client pre-pr-content \
        fixtures-client golden-diff golden-update \
        checklist-validate checklist-generate \
-       perf-baseline
+       perf-baseline debug-schedule
 
 # --- Configuration ---
 
@@ -53,6 +53,7 @@ help:
 	@echo "  make pre-pr-content     Content-scoped pre-PR (schema + cross-ref validation)"
 	@echo ""
 	@echo "  make setup-hooks       Install pre-commit hooks (included in setup)"
+	@echo "  make debug-schedule    Print bevy_ecs schedule graph (diff for PR artifacts)"
 	@echo ""
 	@echo "  GODOT_VERSION=4.6 make setup   Override Godot version"
 
@@ -285,6 +286,12 @@ checklist-generate:
 perf-baseline:
 	@tooling/perf-baseline
 
+# --- Schedule debug (#346) ---
+
+debug-schedule:
+	@echo "Dumping bevy_ecs schedule graph..."
+	@cd server && cargo run -- --dump-schedule
+
 content-ron:
 	cd tooling/content-converter && cargo build --release
 	tooling/content-converter/target/release/content-converter --input content --output content-ron --verbose