Fix subagent instruction conflicts across persona and profiles ...

Persona:
- Fix [STATUS: completed|limit_reached] reference (format was removed)
- Clarify three fields: task / briefing / system_prompt with distinct roles
- Clarify context_transfer vs briefing: transfer = working state, briefing = credentials

Secretary system_prompt:
- Replace vague "write all context to context_transfer" with explicit field breakdown
- task / briefing / system_prompt each described with their purpose
- context_transfer correctly limited to intermediate findings, not credentials

Server admin system_prompt:
- Same fix: explicit field breakdown for spawn_agent
- Remove dangling "see persona" reference for briefing ending

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

Strengthen orchestration mandate: spawn first, inline last ...

secretary/server_admin system prompts:
- Explicit spawning rule: MUST spawn for any sub-task requiring 3+ tool calls
- Additional mandatory triggers listed (research, file processing, remote ops, large output)
- "If in doubt — spawn" as explicit fallback
- AGENT steps: "MANDATORY, never execute inline — defeats the orchestrator model"
- context_transfer pattern: write to scratchpad before spawning, injected automatically

persona.txt:
- Updated SUB-AGENT BRIEFING section: renamed to SUB-AGENTS
- Reflects new context_transfer automatic injection (no longer needs to be in task)
- Added: check [STATUS: ...] in result before deciding next action

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

Audit and trim system prompts (~470 tokens saved) ...

persona.txt:
- Shortened personality paragraph (~30% cuts, no content loss)
- Removed duplicate list_tools instruction
- Removed hardcoded 'developer' profile rule (handled by dynamic profiles block)
- Condensed EXECUTION MODES fundamental blockers to one sentence
- Moved sub-agent briefing boilerplate here (single source of truth)
- Trimmed REFLECTION section (tool description handles the how)
- Removed redundant RESPONSE HYGIENE explanation sentence
- Moved 'never assume file exists' into EXECUTION DISCIPLINE
- Removed DOCUMENTATION section

profiles (all three):
- Replaced ~100-token sub-agent briefing boilerplate with pointer to persona
- developer: removed data persistence code block (covered by _template.py)

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

Move orchestration from persona to profiles; tune per-profile delegation strategy ...

persona.txt now contains only: identity, profile switching, workspace,
response hygiene, memory, and documentation. All orchestration instructions
removed from the global scope.

Each profile gets its own orchestration model:
- secretary: full orchestrator — delegate any 2+ tool-call sub-task to agents,
  scratchpad as blackboard, todo for milestone tracking
- server_admin: heavy orchestrator — one agent per host / per concern,
  parallel delegation, diagnose-before-act discipline
- developer: builder + research delegation — implementation always inline,
  spawn only for large API/codebase research tasks

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

Restructure profiles: directory-based format with config.json + system_prompt.txt ...

Each profile is now a subdirectory under navi/profiles/ containing:
  config.json       — model, temperature, enabled_tools, and other settings
  system_prompt.txt — raw system prompt, editable without touching Python

Added navi/profiles/loader.py for auto-discovery of profile directories.
Removed individual profile .py files (secretary, server_admin, smart_home, developer).
profiles/__init__.py now simply calls load_profiles_from_dir() at import time.

New profiles can be added by creating a directory with the two required files —
no Python changes needed.

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