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/tier1-orchestrator.md

@@ -40,6 +40,18 @@ You MUST use Manual Slop's MCP tools. Native OpenCode tools are unreliable.
 |-------------|----------|
 | `bash` | `manual-slop_run_powershell` |
 
+## Session Start Checklist (MANDATORY)
+
+Before ANY other action:
+1. [ ] Read `conductor/workflow.md`
+2. [ ] Read `conductor/tech-stack.md`
+3. [ ] Read `conductor/product.md`, `conductor/product-guidelines.md`
+4. [ ] Read relevant `docs/guide_*.md` for current task domain
+5. [ ] Check `TASKS.md` for active tracks
+6. [ ] Announce: "Context loaded, proceeding to [task]"
+
+**BLOCK PROGRESS** until all checklist items are confirmed.
+
 ## Primary Context Documents
 Read at session start: `conductor/product.md`, `conductor/product-guidelines.md`