Enhance native toolset and add persistent KV store ...

- Add PostgreSQL-backed KvStore (navi/store/) for session-scoped data.
- Migrate todo and scratchpad from in-memory dicts to KvStore.
- Filesystem: add copy, grep, diff actions; compress description.
- CodeExec: remove language param, expose working_dir in schema.
- ImageView: resize to 1024px JPEG + Content-Type guard for URLs.
- Memory list: return distinct categories instead of all facts.
- SSH: add scp action with upload/download support.
- Update CLAUDE.md (Postgres-only), docs/tools.md, add docs/store.md.
- Fix agent/planning/context_builder async signatures for todo helpers.

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

Refactor: move tool helper modules into _internal subpackage ...

Moves non-tool infrastructure out of navi/tools/ root so that only
actual tool classes live there:

  base.py           → _internal/base.py
  loader.py         → _internal/loader.py
  middleware.py     → _internal/middleware.py
  logging_middleware.py → _internal/logging_middleware.py
  _time_parser.py   → _internal/time_parser.py

All imports updated across core/, api/, mcp/, tools/, and tests/.
No proxy files remain in navi/tools/ root.

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

Clarify knowledge persistence prompts

Integrate proactive knowledge capture into planning and persona ...

- Phase 1 planning: add KNOWLEDGE CAPTURE section to prompt
- Phase 3 planning: add knowledge persistence rule with target selection
- Persona: add "search before save" deduplication instruction
- MCP gnexus-book: add persistence guidance for discovered facts

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

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>

Improve 3D modeling validation prompts

Open artifact links externally on Android

Extract PlanningEngine, ContextBuilder, ToolExecutor from agent.py ...

- navi/core/planning.py: new 3-phase planning pipeline (~390 lines)
- navi/core/context_builder.py: system prompt caching, memory/context injection, goal anchoring (~160 lines)
- navi/core/tool_executor.py: tool execution with middleware chain (~150 lines)
- navi/core/agent.py: reduced from ~1420 to ~770 lines; delegates to extracted classes

All compilation verified.

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