fix: reset regex state in hasEditProposals (#7)

The module-level regexes use the /g flag (required by matchAll in
parseEditProposals). However, RegExp.prototype.test() on a global
regex advances lastIndex, so consecutive calls to hasEditProposals
with the same input alternate between true and false.

Reset lastIndex to 0 before each test call. Added a regression test
that verifies consecutive calls return consistent results.

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: ademczuk

__tests__/edit-parser.test.ts

@@ -84,4 +84,11 @@ describe('hasEditProposals', () => {
   it('returns false for plain text', () => {
     expect(hasEditProposals('no code here')).toBe(false)
   })
+
+  it('returns consistent results on consecutive calls', () => {
+    const text = '[EDIT foo.ts]\n```\ncode\n```'
+    expect(hasEditProposals(text)).toBe(true)
+    expect(hasEditProposals(text)).toBe(true)
+    expect(hasEditProposals(text)).toBe(true)
+  })
 })

lib/edit-parser.ts

@@ -73,5 +73,7 @@ export function parseEditProposals(text: string): EditProposal[] {
 }
 
 export function hasEditProposals(text: string): boolean {
+  EDIT_MARKER_RE.lastIndex = 0
+  FENCED_WITH_PATH_RE.lastIndex = 0
   return EDIT_MARKER_RE.test(text) || FENCED_WITH_PATH_RE.test(text)
 }