feat: audit log, usage tracking UI, OpenAI orchestrator compaction, onboarding + docs

Tool audit log:
- Every orchestrator tool call logged to home/{user}/tool_audit/YYYY-MM-DD.jsonl
- Files panel sidebar: audit log group (collapsed), date-linked read-only table
- Admin endpoints: /api/audit/files, /api/audit/day, /api/audit/recent, /api/audit/stats
- Engine and model name recorded per entry

OpenAI orchestrator improvements:
- Context budget enforcement: 75% of model context_k (min 16k)
- Message compaction: truncates old tool results when approaching budget
- max_rounds respected per model config (intersected with server cap)

OpenRouter onboarding (setup.html, onboarding.py, app.js, settings.html):
- Step 3 of 3: /setup/model with curated model picker
- Chat banner for users on server-default model (informational, not alarmist)
- Settings quick-link card; /setup/model works standalone for existing users

Model registry + session store:
- set_role_config / get_role_config for per-role tool lists and system_append
- session_store: session rename, session name backfill endpoint

UI updates (app.js, index.html, style.css, local_llm.html):
- Role toggle in context panel
- Off-the-record mode
- Agent notes read-only viewer
- OPERATIONS.md loaded at T2+ in context

Documentation:
- HELP.md: full tool table, per-role tool sets, Agent Notes, usage tracking
- TOOLS.md: Agent Notes section, count corrected to 44
- ARCH__SYSTEM.md, ARCH__BACKENDS.md, MASTER.md updated to match reality
- CLAUDE.md: onboarding flow, documentation philosophy sections
- README.md: stack in practice, DeepSeek TUI mention, architecture diagram updated
- TODO__Agents.md: onboarding task completed with deviation notes

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

cortex/model_registry.py

@@ -36,6 +36,7 @@ V2 Schema:
         "credential_id":str | null,     # claude_cli only — references providers.anthropic.credentials
         "account_id":   str | null,     # gemini_api only — references providers.google.accounts
         "context_k":    int,            # context window in k tokens (informational)
+        "max_rounds":   int | null,     # per-model tool-loop cap; null = use orchestrator_max_rounds global
         "tags":         [str],          # user-defined capability tags
       },
     ],
@@ -642,7 +643,9 @@ def remove_host(username: str, host_id: str) -> bool:
 
 def save_model(username: str, model_id: str | None, host_id: str,
                label: str, model_name: str, context_k: int = 0,
-               tags: list[str] | None = None) -> str:
+               tags: list[str] | None = None,
+               max_rounds: int | None = None,
+               tools: bool = True) -> str:
     """Create or update a local_openai model entry. Returns the model ID."""
     data = _load(username)
     tags = tags or []
@@ -654,6 +657,8 @@ def save_model(username: str, model_id: str | None, host_id: str,
                 m["label"]      = label.strip() or model_name.strip()
                 m["model_name"] = model_name.strip()
                 m["context_k"]  = context_k
+                m["max_rounds"] = max_rounds
+                m["tools"]      = tools
                 m["tags"]       = tags
                 _save(username, data)
                 return model_id
@@ -668,6 +673,8 @@ def save_model(username: str, model_id: str | None, host_id: str,
         "provider":   "local",
         "host_id":    host_id,
         "context_k":  context_k,
+        "max_rounds": max_rounds,
+        "tools":      tools,
         "tags":       tags,
     })
     _save(username, data)
@@ -679,7 +686,9 @@ def save_cloud_model(username: str, model_id: str | None,
                      account_id: str | None = None,
                      credential_id: str | None = None,
                      context_k: int = 0,
-                     tags: list[str] | None = None) -> str:
+                     tags: list[str] | None = None,
+                     max_rounds: int | None = None,
+                     tools: bool = True) -> str:
     """
     Create or update an Anthropic or Google model entry. Returns the model ID.
 
@@ -698,6 +707,8 @@ def save_cloud_model(username: str, model_id: str | None,
         "model_name": model_name.strip(),
         "provider":   provider,
         "context_k":  context_k,
+        "max_rounds": max_rounds,
+        "tools":      tools,
         "tags":       tags,
     }
     if account_id: