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---

package.json

@@ -1,11 +1,11 @@
 {
-  "name": "@continuous-intelligence/ci",
+  "name": "@continuous-intelligence/ciagent",
   "version": "0.5.0",
   "description": "Fully autonomous AI-driven software engineering harness - Continuous Intelligence",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",
   "bin": {
-    "ci": "./dist/cli/index.js"
+    "ciagent": "./dist/cli/index.js"
   },
   "files": [
     "dist/",
@@ -22,7 +22,7 @@
     "prepublishOnly": "npm run build",
     "install-opencode": "node scripts/postinstall.js"
   },
-  "keywords": ["ci", "autonomous", "ai", "software-engineering", "agent", "multi-project"],
+  "keywords": ["ciagent", "autonomous", "ai", "software-engineering", "agent", "multi-project"],
   "license": "MIT",
   "engines": {
     "node": ">=18.0.0"