Add deterministic line-based file editing (edit_lines), rating UI fix, and session refresh ...

- filesystem.py: add edit_lines action (deterministic line ops via operations array)
           + numbered param for read (1-based line numbers in output)
           + clarify four editing modes in tool description
- chat.js: fix rating IDs for streaming messages (assign h_ ID on stream_end)
- SessionList.vue: mobile pull-to-refresh with PTR_THRESHOLD=80
- AppSidebar.vue: desktop refresh button next to Conversations header
- planning.py: knowledge source assessment in Phase 1
- debug panel: MCP servers tab + resolved tools per profile
- NAVI.md: reposition as neutral quick-reference

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

Inject MCP server instructions into system prompt ...

- McpClient: collect instructions from MCP initialize handshake
- McpServerConfig: add 'instructions' field for Navi-side overlay
- McpManager.get_instructions(): merge server + config instructions
- ContextBuilder: new _mcp_context_msg() injects MCP server
  descriptions into every LLM context as a system message
- Agent passes mcp_manager to ContextBuilder
- mcp_servers.json: add overlay instructions for gnexus-book

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

Refactor MCP integration: server groups in profiles ...

- mcp_servers.json: add 'groups' (read/write/admin) for gnexus-book
- AgentProfile: new 'mcp_servers' field (server_name -> group list)
- Profile loader: parse and persist 'mcp_servers' in config.json
- Agent._tool_list(): expands mcp_servers into concrete tool names
  via McpManager.resolve_group(), wildcard '*' supported
- /agents/profiles API: includes 'mcp_servers' in response
- Profiles no longer list individual mcp_ tools in 'enabled_tools'
- discuss: gnexus-book read group
- server_admin: gnexus-book read+write+admin groups

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

Connect gnexus-book MCP server and enable in profiles ...

- mcp_servers.json: SSE transport to 192.168.1.170:8001
- server_admin profile: all 16 gnexus-book tools
- discuss profile: read-only gnexus-book tools (docs + inventory)

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