feat: MVP — move files, rewrite imports, atomically

- core: gitignore-aware index (ignore crate), forward/reverse import graph,
  relative-specifier math, pure-data move plans
- apply: rewrite-first + rename-last with fsync, temp+rename, full rollback
  (incl. stale-plan detection before any write); unified diff for dry-run
- cli: mv + check commands, human output, --json envelope with stable error
  codes (SOURCE_NOT_FOUND, TARGET_EXISTS, ...) and hints; exit codes 0/1/2
- parser/core split into submodules to keep files <=250 lines
- tests: 37 unit + 10 e2e + 2 doctests; fixtures tests/typescript/{basic,normal,complex}
- docs: SKILL.md synced (no --force in Phase 1), EXAMPLES.md
- plan: AI/agent support done; Phase 1.5 = Java niche

tests/typescript/basic/app.ts

@@ -0,0 +1,5 @@
+import { sum } from "./lib/sum";
+
+export function main(): number {
+  return sum(1, 2);
+}

tests/typescript/basic/lib/sum.ts

@@ -0,0 +1,3 @@
+export function sum(a: number, b: number): number {
+  return a + b;
+}

tests/typescript/basic/package.json

@@ -0,0 +1 @@
+{ "name": "basic" }