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/core/error-recovery.test.ts

@@ -2,16 +2,16 @@ import * as fs from "node:fs";
 import * as path from "node:path";
 import * as os from "node:os";
 import { ErrorRecovery } from "../core/error-recovery.js";
-import { DEFAULT_CI_CONFIG } from "../types/config.js";
+import { DEFAULT_CIAGENT_CONFIG } from "../types/config.js";
 
 describe("ErrorRecovery", () => {
   let tempDir: string;
   let recovery: ErrorRecovery;
 
   beforeEach(() => {
-    tempDir = fs.mkdtempSync(path.join(os.tmpdir(), "ci-recovery-test-"));
-    fs.mkdirSync(path.join(tempDir, ".ci"), { recursive: true });
-    recovery = new ErrorRecovery(DEFAULT_CI_CONFIG, tempDir);
+    tempDir = fs.mkdtempSync(path.join(os.tmpdir(), "ciagent-recovery-test-"));
+    fs.mkdirSync(path.join(tempDir, ".ciagent"), { recursive: true });
+    recovery = new ErrorRecovery(DEFAULT_CIAGENT_CONFIG, tempDir);
   });
 
   afterEach(() => {