feat(agent): subagent tool paralel + auto-load AGENTS.md + verify cek setelah edit

Lanjutan audit alur AI agent (round 2), mengisi celah yang tersisa dari
perpbaikan paralel tool di loop utama (74b1ad4) agar lebih mirip Claude Code.

- feat(subagent): eksekusi batch tool read-only paralel di subagent engine
  (engine.rs). Tool::run sinkron, jadi pakai scoped OS thread (bounded
  window 8); hasil dipertahankan dalam urutan panggilan asli. Batch dengan
  tool mutating jatuh balik ke jalur sequential aman.
- feat(agent): auto-load AGENTS.md/CLAUDE.md/.cursorrules ke system prompt
  tiap turn (seperti Claude Code load AGENTS.md saat startup). Fungsi
  main_agent_prompt_with_project_context menempel blok PROJECT CONTEXT;
  dibaca dari workspace root pertama & dibatasi 12k char.
- feat(prompt): arahan VERIFY AFTER EDIT — setelah edit/write, agent wajib
  jalankan cargo check/clippy/test (atau lint/test sesuai stack) via bash
  sebelum mengakhiri turn; perbaiki error yang terlihat, jangan klaim
  'compiles/works' tanpa hasil nyata.
- feat(infra): build_rich_context kini membaca AGENTS.md & CLAUDE.md juga
  (untuk explore_codebase/scout).
- test: +3 subagent engine (order paralel, kecepatan konkuren, fallback
  mutating), +2 domain prompt (konteks proyek & fallback kosong).

apps/application/src/agent/turn_service.rs

@@ -5,7 +5,7 @@ use tracing::{debug, info, warn};
 
 use zesdex_domain::agent::{AgentTurnParams, TurnEvent};
 use zesdex_domain::core::{ChatMessage, StreamEvent, ToolDef};
-use zesdex_domain::main_agent_prompt;
+use zesdex_domain::main_agent_prompt_with_project_context;
 
 use super::ToolExecutor;
 use crate::ports::ProviderService;
@@ -111,6 +111,46 @@ fn conversation_chars(messages: &[ChatMessage]) -> usize {
         .sum()
 }
 
+/// The maximum combined size (characters) of project-rule files injected into
+/// the system prompt, so a huge AGENTS.md cannot blow the context window.
+const PROJECT_CONTEXT_MAX_CHARS: usize = 12_000;
+
+/// Case-insensitive rule filenames auto-loaded from the workspace root into
+/// the system prompt, matching the Claude-Code/AGENTS.md convention.
+const RULE_FILENAMES: [&str; 6] = [
+    "AGENTS.md",
+    "agent.md",
+    "CLAUDE.md",
+    "claude.md",
+    ".cursorrules",
+    ".zesdexrules",
+];
+
+/// Build a compact "project context" block from the repo's convention files
+/// (AGENTS.md, CLAUDE.md, .cursorrules, …) found at the workspace root.
+///
+/// Follows the Claude-Code convention of loading AGENTS.md at startup so the
+/// model starts each turn with the repo's rules. Reads are best-effort and
+/// capped at [`PROJECT_CONTEXT_MAX_CHARS`] total; missing files are skipped.
+fn build_project_context(root: &std::path::Path) -> String {
+    let mut ctx = String::new();
+    for file in RULE_FILENAMES {
+        let full = root.join(file);
+        if let Ok(content) = std::fs::read_to_string(&full) {
+            ctx.push_str(&format!("\n### {file}\n```\n{}\n```", content.trim()));
+        }
+    }
+    let context = ctx.trim().to_string();
+    if context.len() <= PROJECT_CONTEXT_MAX_CHARS {
+        return context;
+    }
+    context
+        .chars()
+        .take(PROJECT_CONTEXT_MAX_CHARS)
+        .collect::<String>()
+        + "\n...[project context truncated]"
+}
+
 /// Track repeated tool-call errors so the loop can recover instead of
 /// burning iterations retrying the same failing tool.
 #[derive(Default)]
@@ -341,9 +381,17 @@ impl<P: ProviderService, T: ToolExecutor> super::AgentTurnService for AgentTurnS
 
         // Insert system prompt at position 0 once and keep it there for the
         // entire turn, avoiding per-iteration clones of the full message list.
+        // Auto-load repo conventions (AGENTS.md / CLAUDE.md / .cursorrules)
+        // from the first workspace root, like Claude Code does at startup.
+        let project_context = params
+            .workspace_roots
+            .first()
+            .map(|root| build_project_context(root))
+            .unwrap_or_default();
+        let system_prompt = main_agent_prompt_with_project_context(&project_context);
         params
             .messages
-            .insert(0, ChatMessage::system(main_agent_prompt()));
+            .insert(0, ChatMessage::system(system_prompt));
         let original_count = params.messages.len();
 
         // Estimate request complexity from the last user message.