docs: overhaul documentation for consistency with implementation

Complete documentation rewrite to match the current codebase:

- README: add benefits section (process consistency, token savings with
  estimates, project isolation, continuous planning, feedback loops,
  role-based prompts, atomic operations, audit trail), task workflow
  with state diagram, model-to-role mapping tables, installation guide
- New TOOLS.md: complete reference for all 11 tools with parameters,
  behavior, and execution guards
- New CONFIGURATION.md: full config reference for openclaw.json,
  projects.json, heartbeat, notifications, workspace layout
- Fix tool names across all docs: task_pickup→work_start,
  task_complete→work_finish
- Fix tier model: QA has reviewer/tester levels, not flat "qa"
- Fix config schema: nested models.dev.*/models.qa.* structure
- Fix prompt path: projects/roles/ not projects/prompts/
- Fix worker state: uses "level" field not "model"/"tier"
- Fix MANAGEMENT.md: remove incorrect model references
- Fix TESTING.md: update model config example to nested structure
- Remove VERIFICATION.md (one-off checklist, no longer needed)
- Add cross-references between all docs pages

https://claude.ai/code/session_01R3rGevPY748gP4uK2ggYag

docs/TESTING.md

@@ -59,10 +59,15 @@ npm run test:ui
       "devclaw": {
         "config": {
           "models": {
-            "junior": "anthropic/claude-haiku-4-5",
-            "medior": "anthropic/claude-sonnet-4-5",
-            "senior": "anthropic/claude-opus-4-5",
-            "qa": "anthropic/claude-sonnet-4-5"
+            "dev": {
+              "junior": "anthropic/claude-haiku-4-5",
+              "medior": "anthropic/claude-sonnet-4-5",
+              "senior": "anthropic/claude-opus-4-5"
+            },
+            "qa": {
+              "reviewer": "anthropic/claude-sonnet-4-5",
+              "tester": "anthropic/claude-haiku-4-5"
+            }
           }
         }
       }