feat(server): skills v1 — parser, tools, /api/skills, mount

- /data/skills mount (host: /opt/skills)
- skill_find, skill_use, skill_resource added to default read-only
  tool set; opt-in for agents with explicit tools: whitelist
- AGENTS.md builtin agents drop explicit tools: arrays to inherit
  the new default (now includes skill tools)
- POST /api/chats/:id/skill_invoke for slash-command flow
- 19 SKILL.md files seeded at /opt/skills/ across 6 source groups

AGENTS.md

@@ -3,7 +3,6 @@
 ## Code Reviewer
 ---
 temperature: 0.3
-tools: [view_file, list_dir, grep, find_files]
 description: Reviews code for bugs, security issues, and maintainability. Read-only.
 ---
 You review code. Find real problems, not style nits.
@@ -33,7 +32,6 @@ If nothing critical or major, say so in one line. Do not pad.
 ## Debugger
 ---
 temperature: 0.2
-tools: [view_file, list_dir, grep, find_files]
 description: Diagnoses bugs from error messages, logs, or described symptoms.
 ---
 You diagnose bugs. Form a hypothesis, prove it with evidence from the code.
@@ -62,7 +60,6 @@ Output:
 ## Refactorer
 ---
 temperature: 0.3
-tools: [view_file, list_dir, grep, find_files]
 description: Proposes refactors for clarity, deduplication, or decoupling. Read-only — outputs plans, not edits.
 ---
 You propose refactors. You do not apply them. The user applies via OpenCode or Claude Code.
@@ -95,7 +92,6 @@ Output:
 ## Architect
 ---
 temperature: 0.5
-tools: [view_file, list_dir, grep, find_files]
 description: Designs new features, modules, or architectural changes. Outputs a build plan.
 ---
 You design. You produce build plans, not code.
@@ -128,7 +124,6 @@ Output:
 ## Security Auditor
 ---
 temperature: 0.2
-tools: [view_file, list_dir, grep, find_files]
 description: Audits code for security vulnerabilities. Read-only.
 ---
 You audit for security issues. Concrete findings only, no generic warnings.
@@ -165,7 +160,6 @@ If the code is clean, say so. Do not invent findings.
 ## Prompt Builder
 ---
 temperature: 0.4
-tools: [view_file, list_dir, grep, find_files]
 description: Builds prompts for OpenCode, Claude Code, or BooCode dispatch.
 ---
 You write prompts that another coding agent will execute. Your output is the prompt, not the work.