fix(arguments): route "חשב טיעונים" through the legal-analyst agent

The /aggregate-arguments endpoint ran an in-container BackgroundTask that
called claude_session (the local `claude` CLI) — which does not exist in the
FastAPI container. The button silently produced nothing, and on `force` it
destructively DELETEd existing arguments *before* the doomed LLM call.

Replace the inline task with the established delegation pattern used by
"חלץ עובדות שמאיות" (extract-appraiser-facts): a cheap in-container DB
pre-check (no_claims / exists), then a Paperclip wakeup of the company's
legal-analyst, which runs mcp__legal-ai__aggregate_claims_to_arguments
locally (where the CLI lives) and reports back. `force` now runs locally too,
so delete+recompute are atomic on the host — no more destructive failure.

Frontend: AggregateArgumentsResult becomes a discriminated union
(queued | no_claims | exists | skipped) and the toast is status-accurate
instead of the misleading fixed "refresh in a minute".

Invariants: G12 (Paperclip touch confined to paperclip_client behind the
agent_platform_port), G2 (replaces the broken path, no parallel capability),
engineering §6 (explicit statuses, no silent swallow).

UI change is logic/toast only (no visual-layout change) — within the
Claude-Design-gate bug-fix exemption. Richer inline status panels deferred
to the gate.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web/agent_platform_port.py

@@ -56,6 +56,7 @@ from web.paperclip_client import (
     restore_project as pc_restore_project,
     update_project_name as pc_update_project_name,
     wake_analyst_for_appraiser_facts as pc_wake_analyst_for_appraiser_facts,
+    wake_analyst_for_argument_aggregation as pc_wake_analyst_for_argument_aggregation,
     wake_ceo_agent as pc_wake_ceo,
     wake_ceo_for_feedback_fold as pc_wake_ceo_for_feedback_fold,
     wake_curator_for_final as pc_wake_curator_for_final,
@@ -99,6 +100,7 @@ __all__ = [
     "pc_wake_curator_for_final",
     "pc_wake_for_precedent_extraction",
     "pc_wake_analyst_for_appraiser_facts",
+    "pc_wake_analyst_for_argument_aggregation",
     # comments / interactions
     "pc_post_comment",
     "pc_get_issue_comments",