Fix MCP names and profile API format consistency ...

- Replace stale mcp__navi_web__* / mcp__navi_3d__* names with canonical
  mcp__navi-web__* / mcp__navi-3d__* across prompts and key_tools.
- Update /agents/profiles and /admin/profiles endpoints to expose
  tools.agent / tools.subagent instead of deprecated enabled_tools fields.
- Update docs/mechanics.md to reference the new tools structure.
- Archive stale docs/visual.html.

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

Add NAVI_AUTH_ENABLED switch for optional auth ...

- Add navi_auth_enabled setting (default true) to navi/config.py and .env.example
- When disabled, treat every request as anonymous admin user (id='anonymous')
- Create/update fixed anonymous navi_users row on startup
- Bypass OAuth/cookie/API-token resolution in navi/auth/deps.py
- Update /auth/status to return {enabled, configured}
- Log security warning on startup when auth is disabled
- Update webclient: skip fetchMe/login screen, show Local mode footer,
  expose /admin link, warn in API keys panel
- Rebuild webclient production bundle
- Add unit and integration tests for no-auth mode
- Update docs: auth.md, config.md, api.md, api_tokens.md, sessions.md,
  websocket.md, mechanics.md, index.md

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

Migrate MCP tool naming from mcp:server:tool to mcp__server__tool ...

The colon separator (mcp:server:tool) confuses many LLMs during
tool-calling because colons appear in schemas and URLs. Switch to
double-underscore separator (mcp__server__tool) for robust parsing.

Key changes:
- navi/mcp/tools.py: add build_mcp_name(), parse_mcp_name(), is_mcp_tool()
- navi/core/tool_executor.py: update _resolve_tool() with new helpers
  and legacy colon fallback for old sessions
- navi/core/tool_utils.py, subagent_runner.py: use build_mcp_name()
- navi/api/routes/{admin,agents}.py: prefix via build_mcp_name()
- navi/tools/{list_tools,reload_tools}.py: migrated
- All profile configs + system_prompt.txt: replace mcp: with mcp__
- manuals/{model_3d,lint_scad,render_3d,spawn_agent}.md: updated
- mcp_servers.d/gnexus-book.json: instructions updated
- docs/{api,profiles,tools,mechanics,visual.html}: updated
- tests: test_tool_executor.py and test_mcp.py aligned

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Fix review issues: KV-store NULL, SVG messages, filesystem tests + docs ...

Bugs fixed:
- filesystem.py: add missing `import re` (grep was broken in production)
- image_view.py: consistent SVG rejection message for URL and file paths
- store/__init__.py: normalize user_id None→'' to prevent duplicate rows
  in unique constraint for anonymous sessions; add DDL migration for
  existing NULL values

Tests:
- Add 10 unit tests for filesystem copy, grep, diff operations

Documentation:
- agent.md: document streaming guard wrapper, system prompt caching,
  ContextVar restoration in subagents
- tools.md: document middleware hooks
- websocket.md: document image upload limits and concurrent run guard
- store.md: document user_id normalization
- mechanics.md: mark newly-documented mechanics as documented

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Add comprehensive mechanics catalog (docs/mechanics.md) ...

Master catalog of all mechanisms in the Navi project:
- 80+ mechanics catalogued across all subsystems
- Each with description, config flags, source files, documentation status
- 50 undocumented mechanics explicitly listed
- Cross-reference index for feature planning
- Updated docs/index.md to link the catalog

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>