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>

McpTool: auto-inject session_id + normalize navi-3d paths ...

- McpTool.execute() now forces the real session_id from current_session_id
  ContextVar, preventing LLM hallucinations of wrong UUIDs (ghost-session bug).
- For navi-3d MCP server, source_path/output_path are normalized to basename
  to prevent double path nesting when the LLM passes full relative paths.
- Updated MCP tool descriptions to ask for filenames only.
- Added system prompt instructions in context_builder and subagent_runner
  reminding the model to pass bare filenames to navi-3d tools.

396 passed, 1 skipped

Rename MCP tools to mcp:server:tool format and restore human-readable names ...

- Core naming: mcp_server_tool → mcp:server:tool (colon-delimited)
- navi-web tools: search/view/request → web_search/web_view/http_request
- navi-3d tools: compile_scad/render_stl/lint_scad (unchanged names)
- Updated all profile configs, system prompts, docs, manuals, tests
- Added new lint_scad.md manual
- Fixed modeler_3d prompt stale references (scad_lint, model_3d, render_3d)
- All 240 tests pass

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

Migrate 3D modeling tools to standalone MCP server navi-3d ...

Phase 0 — Fix MCP error propagation:
- McpClient.call_tool now returns (output, is_error) tuple
- McpTool.execute sets success=False when MCP reports isError=True
- Fixes silent failures where MCP errors looked like success

Phase 1 — Create mcp-server-navi-3d:
- New standalone MCP server in mcp-servers/navi-3d/
- Tools: compile_scad, render_stl, lint_scad
- Session-scoped path resolution via SESSION_FILES_DIR env
- Anti-escape validation for security
- Includes tests/unit/test_scad_analyze.py

Phase 2 — Remove from Navi core:
- Deleted navi/tools/{model_3d,render_3d,scad_lint}.py
- Removed from registry.py builtins and navi/tools/__init__.py
- Updated pyproject.toml testpaths to exclude mcp-servers/

Phase 3 — Wire into Navi config:
- Added navi-3d block to mcp_servers.json (SSE on :8002)
- Updated modeler_3d profile: mcp_servers + updated system_prompt
- All old tool names replaced with mcp_navi-3d_* equivalents

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

Clarify knowledge persistence prompts

Add MCP server support and fix memory tools user isolation ...

MCP integration:
- New navi/mcp/ package: client, manager, config, tools
- ToolRegistry learns register_external() for MCP tools
- reload_tools reconnects MCP servers on hot reload
- New built-in mcp_status tool
- Startup/shutdown wiring for MCP connections
- 12 new tests (unit + integration with real stdio server)

Memory tools fix:
- memory, memory_save, memory_search, memory_forget now read
  current_user_id from tool context and pass it to MemoryStore
- Fixes invisible facts for authenticated users

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