docs(rebrand): rename & rebrand CI → CIAgent across all documentation, templates, and scripts

- README.md: title, project name, CLI commands, .ci/ → .ciagent/, ci-files → ciagent-files, CI Modification → CIAgent Modification
- AGENTS.md: title, project name, architecture tree, agent count (18→19), test count (25→31 suites, 218→370 tests), version (0.4.0→0.6.0), ci-files → ciagent-files, CIConfig → CIAgentConfig, CiMetadata → CIAgentMetadata, .ci/ → .ciagent/
- templates/DECISIONS.md: .ci/audit/ → .ciagent/audit/, ci audit → ciagent audit
- scripts/postinstall.js: CI postinstall → CIAgent postinstall
- scripts/install.sh: CI → CIAgent, ci-init → ciagent-init, INSTALL COMPLETE banner
- opencode/ci/workflows/*.md (11 files): .ci/ → .ciagent/, CI → CIAgent project name, ci-command → ciagent-command usage lines
- opencode/ci/references/*.md (5 files): .ci/ → .ciagent/, CI → CIAgent project name, ci-files → ciagent-files references
- opencode/ci/contexts/*.md (3 files): .ci/ → .ciagent/, CI → CIAgent project name
- opencode/agents/ci-*.md (18 files): .ci/ → .ciagent/, CI → CIAgent project name
- opencode/command/ci-*.md (11 files): CI → CIAgent project name

Preserved: ---ci---/---/ci--- markers, opencode/ci/ dir paths, ci-*.md filenames, ci listProjects()/ci setActiveProject() API names, repo URLs

---ci---
phase: 1
milestone: v0.6
plan: 01-01
task: 01-01-01
status: execute
---/ci---

opencode/agents/ci-doc-writer.md

@@ -1,5 +1,5 @@
 ---
-description: Writes and updates CI project documentation files — grounded in the live codebase, verifies factual claims. Documentation updates are committed with ---ci--- blocks.
+description: Writes and updates CIAgent project documentation files — grounded in the live codebase, verifies factual claims. Documentation updates are committed with ---ci--- blocks.
 color: "#90EE90"
 tools:
   read: true
@@ -11,20 +11,20 @@ tools:
 ---
 
 <role>
-You are a CI doc writer. You write and update CI project documentation files, grounded in the live codebase. You verify factual claims against actual code.
+You are a CIAgent doc writer. You write and update CIAgent project documentation files, grounded in the live codebase. You verify factual claims against actual code.
 
-Documentation updates are committed with `---ci---` blocks. You update `.ci/` static files (PROJECT.md, ARCHITECTURE.md, ROADMAP.md, REQUIREMENTS.md) with discipline.
+Documentation updates are committed with `---ci---` blocks. You update `.ciagent/` static files (PROJECT.md, ARCHITECTURE.md, ROADMAP.md, REQUIREMENTS.md) with discipline.
 
 **CRITICAL: Mandatory Initial Read**
 If the prompt contains a `<files_to_read>` block, you MUST use the Read tool to load every file listed there before performing any other actions.
 </role>
 
 <project_context>
-If .ci/config.json has projects[] with length > 0, you are in multi-project mode.
-- Read active_project from .ci/config.json
+If .ciagent/config.json has projects[] with length > 0, you are in multi-project mode.
+- Read active_project from .ciagent/config.json
 - All commits must include `project: <active_project>` in ---ci--- block
 - Branch names are prefixed with <slug>/ in multi-project mode
-- .ci/ files are in .ci/<slug>/ subdirectories
+- .ciagent/ files are in .ciagent/<slug>/ subdirectories
 If single-project mode (projects[] empty or absent), use existing conventions.
 
 Before writing, load context from git first:
@@ -32,7 +32,7 @@ Before writing, load context from git first:
 1. Run `git log --max-count=20` for recent changes that affect docs
 2. Use GitContext.getDecisions() for decisions to document
 3. Use GitContext.getRequirementsCoverage() for current coverage
-4. Read the existing .ci/ file you're updating
+4. Read the existing .ciagent/ file you're updating
 5. Read the relevant source code to verify claims
 </project_context>
 
@@ -51,7 +51,7 @@ Before writing any factual claim:
 
 ## Step 3: Write/Update Documentation
 
-Use CiFiles methods to write .ci/ files:
+Use CiFiles methods to write .ciagent/ files:
 - writeProjectMd(project, reason)
 - writeArchitectureMd(architecture)
 - writeRoadmapMd(roadmap)