Overhaul agent quality — prompts, tools, config, compression

- Rewrite system prompt: structured sections, explicit tool descriptions
  with full SKILL.md descriptions, multi-agent awareness
- Add write_file skill for creating/modifying workspace files
- Per-template config passthrough: temperature, num_predict, context_size,
  compress settings, max_tool_rounds, max_response_lines
- Bump defaults: 1024 output tokens (was 512), 500-char deque (was 200),
  250-token summaries (was 150), compress threshold 16 (was 12), keep 8 (was 4)
- Cache compression by content hash — no redundant summarization
- Update all 5 templates with tuned settings per role

skills/write_file/SKILL.md

@@ -0,0 +1,17 @@
+---
+name: write_file
+description: Write content to a file in /workspace. Creates parent directories if needed. Use this to save scripts, reports, data, or any output you want to persist.
+parameters:
+  path:
+    type: string
+    description: Path to write (must be under /workspace)
+    required: true
+  content:
+    type: string
+    description: Content to write to the file
+    required: true
+  append:
+    type: boolean
+    description: If true, append to existing file instead of overwriting (default false)
+    required: false
+---

skills/write_file/run.py

@@ -0,0 +1,32 @@
+#!/usr/bin/env python3
+"""Write content to a file under /workspace."""
+import json
+import os
+import sys
+
+args = json.loads(sys.stdin.read())
+path = args.get("path", "")
+content = args.get("content", "")
+append = args.get("append", False)
+
+WORKSPACE = os.environ.get("WORKSPACE", "/workspace")
+
+resolved = os.path.realpath(path)
+if not resolved.startswith(WORKSPACE + "/") and resolved != WORKSPACE:
+    print(f"[error: path must be under {WORKSPACE}]")
+    sys.exit(0)
+
+if os.path.isdir(resolved):
+    print(f"[error: {path} is a directory]")
+    sys.exit(0)
+
+try:
+    os.makedirs(os.path.dirname(resolved), exist_ok=True)
+    mode = "a" if append else "w"
+    with open(resolved, mode) as f:
+        f.write(content)
+    size = os.path.getsize(resolved)
+    action = "appended to" if append else "wrote"
+    print(f"[{action} {path} ({size} bytes)]")
+except Exception as e:
+    print(f"[error: {e}]")