Pass explicit ToolContext to tools instead of hidden ContextVars ...

Add ToolContext dataclass (session_id, event_sink, stop_event, model,
user_id, user_role, user_info) and thread it through the execution chain:
Agent._execute_tools_with_sink → ToolExecutor → tool.execute().

All ~25 tools updated to accept ctx parameter. Tools that previously
read ContextVar now prefer ctx when provided, falling back to
ContextVar for backward compatibility.

Tests updated to pass ToolContext explicitly — no more test fixtures
that set current_session_id / current_user_id ContextVars.

ContextVar setters remain as fallback for non-tool consumers
(ai_helper, context_builder, planning) and will be removed in a
follow-up refactor.

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

Add inherit_system_prompt and is_subagent_only mechanisms ...

- inherit_system_prompt: subagent parameter to prepend parent's system
  prompt as a base layer before subagent specialisation
- is_subagent_only: profile flag blocking switch_profile, allowing
  spawn_agent only; shown with [subagent only] tag in list_profiles
- Document both in docs/profiles.md and docs/tools.md

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>

Make profile switching autonomous: switch immediately, inform after ...

Previously Navi asked for permission before switching profiles.
Updated both the injected profiles block in the system prompt and the
switch_profile tool description to explicitly say: switch on your own
judgment, do not ask, then inform the user which profile is active and why.

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

Fix ssh_exec error reporting + circular import in switch_profile ...

ssh_exec:
- Non-zero exit status: output (stdout/stderr) now included in error
  field so model can actually see why the command failed
- All error cases: error field now contains human-readable message
  instead of short code (no_target, permission_denied, timeout)
- Named connections from ssh_hosts.json: default known_hosts=none
  same as ad-hoc connections (was missing, caused host key failures)

switch_profile:
- Move ProfileSwitched import inside execute() to break circular
  import: tools.__init__ → switch_profile → core.events → core.agent
  → core.registry → tools

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

Profile switch: emit WS event so client updates UI immediately ...

ProfileSwitched event emitted by switch_profile tool via current_event_sink.
Client handles profile_switched: updates chat header, profile selector,
and local sessions[] — no page refresh needed.

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

Add switch_profile tool for automatic profile switching ...

Navi can now switch her own profile mid-session when the task domain
changes. The new profile (tools + system prompt) takes effect from the
next user message. Injected with session_store + profile_registry like
SpawnAgentTool. Added to all profiles' enabled_tools and persona.

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