tools: list_tools defaults to the profile the run executes as ...

Asking "what tools do I have?" required the agent to know its own profile id
— and to be right about it after a switch_profile had moved the session. The
run knows: run_stream now publishes the active profile id (re-published when
switch_profile reloads the run) alongside the model, SubAgentRunner publishes
its own rather than inheriting the parent's, and ToolContext carries it into
every execute() call.

list_tools reads that when profile_id is omitted, so the bare call answers the
question, and it says which profile it assumed ("current profile") so the
answer cannot be mistaken for another profile's.

scope='agent'|'subagent' selects which of the profile's two toolsets to list —
the set spawn_agent would hand a sub-agent running that profile, which is a
different list and until now had no way to be inspected.

Item D of the list_tools plan, kept separate from the accuracy/compactness work.

tools: list_tools tells the truth and costs a tenth of the context ...

The tool read the profile config, not the registry: a tool the config declares
but nothing registered — mcp__navi_ui__render_component, whose server never
connects — was advertised as callable, and the agent walked into "tool not
found" (28 such warnings on prod). It now resolves every name against the live
registry and reports the rest separately as "Not registered", so a phantom
entry reads as a broken server, not as a tool to try.

It also returned every description it could find. For server_admin that was
125 tools and 35 316 bytes per call — ~9k tokens to answer "do I have anything
for ssh". Names are now grouped by source (native, then one section per MCP
server) with descriptions behind verbose, and query filters by substring over
names and descriptions: the ssh question costs 88 bytes instead of 35 KB, and
a plain listing drops to 3.7 KB (9.5x smaller).

Tests cover the phantom-tool case, query matching by name and by description,
and the size property that makes names-only the default.