docs(post-mortem): Apply session start checklists and edit tool warnings

From gui_decoupling_controller track post-mortem:

workflow.md:
- Add mandatory session start checklist (6 items)
- Add code style section with 1-space indentation enforcement
- Add native edit tool warning with MCP alternatives

AGENTS.md:
- Add critical native edit tool warning
- Document MCP tool alternatives for file editing

tier1-orchestrator.md:
- Add session start checklist

tier2-tech-lead.md:
- Add session start checklist
- Add tool restrictions section (allowed vs forbidden)
- Add explicit delegation pattern

tier3-worker.md:
- Add task start checklist

tier4-qa.md:
- Add analysis start checklist

.opencode/agents/tier4-qa.md

@@ -43,6 +43,14 @@ You MUST use Manual Slop's MCP tools. Native OpenCode tools are unreliable.
 You operate statelessly. Each analysis starts fresh.
 Do not assume knowledge from previous analyses or sessions.
 
+## Analysis Start Checklist (MANDATORY)
+
+Before analyzing:
+1. [ ] Read error output/test failure completely
+2. [ ] Identify affected files from traceback
+3. [ ] Use skeleton tools for files >50 lines (`manual-slop_py_get_skeleton`)
+4. [ ] Announce: "Analyzing: [error summary]"
+
 ## Analysis Protocol
 
 ### 1. Understand the Error