refactor(rebrand): rename & rebrand CI → CIAgent across all source and test files

- Type renames: CIConfig → CIAgentConfig, DEFAULT_CI_CONFIG → DEFAULT_CIAGENT_CONFIG
- Type renames: CiMetadata → CIAgentMetadata, ParsedCiCommit → ParsedCIAgentCommit
- Function renames: initCI → initCIAgent, isCIInitialized → isCIAgentInitialized
- Function renames: extractCiBlock → extractCIAgentBlock, parseCiBlock → parseCIAgentBlock
- Class renames: CiFiles → CIAgentFiles
- Import paths: ci-files.js → ciagent-files.js
- Directory paths: .ci/ → .ciagent/ across all source and test files
- Check names: ".ci directory exists" → ".ciagent directory exists"
- Check names: "CI config valid" → "CIAgent config valid"
- Temp dir names: ci-*-test- → ciagent-*-test-
- CLI examples: "ci init" → "ciagent init"
- Fix deepMerge infinite recursion bug in config.ts
- ---ci---/---/ci--- block markers preserved unchanged
- All 31 test suites, 370 tests passing

---ci---
phase: 1
milestone: v0.5
plan: 07
task: 07-01-01
status: execute
---/ci---

src/verification/behavioral.ts

@@ -108,8 +108,8 @@ export class BehavioralVerification extends VerificationLayer {
   }
 
   private checkSpecificationRequirements(projectPath: string): VerificationCheck {
-    const reqPath = path.join(projectPath, ".ci", "REQUIREMENTS.md");
-    const projectPath_md = path.join(projectPath, ".ci", "PROJECT.md");
+    const reqPath = path.join(projectPath, ".ciagent", "REQUIREMENTS.md");
+    const projectPath_md = path.join(projectPath, ".ciagent", "PROJECT.md");
 
     const specPath = reqPath;
     if (!fs.existsSync(specPath)) {
@@ -189,7 +189,7 @@ export class BehavioralVerification extends VerificationLayer {
   private checkPlanMustHaves(projectPath: string, phase: number): VerificationCheck {
     const roadmapPath = path.join(
       projectPath,
-      ".ci",
+      ".ciagent",
       "ROADMAP.md"
     );
 
@@ -252,7 +252,7 @@ export class BehavioralVerification extends VerificationLayer {
         ciBlockRegex.lastIndex = 0;
       }
 
-      const reqPath = path.join(projectPath, ".ci", "REQUIREMENTS.md");
+      const reqPath = path.join(projectPath, ".ciagent", "REQUIREMENTS.md");
       if (!fs.existsSync(reqPath)) {
         return this.check(
           "Requirement test coverage via git log",