Replace portfolio/holdings with persistent track list across finance workflows

[bilalbayram]

Summary

Portfolio-based workflows are creating repeated failures and unnecessary friction (especially when commands require stored holdings just to run). Replace portfolio/holdings as a core dependency with a lightweight persistent track list of tickers the user follows.

Scope

• Remove portfolio-first assumptions from finance command flows.
• Introduce a persistent track-list model for tickers users want to monitor regularly.
• Update /financial-government-trading, /report-insiders, and related workflows to use track list when ticker is omitted.
• Ensure omitted ticker still works in a global-only mode when track list is empty.
• Deprecate/remove portfolio-specific command/tool UX (/portfolio, /report-portfolio) once replacements are in place.
• Migrate existing stored portfolio tickers into track list once (best-effort), then stop using holdings data for command gating.
• Update permissions, docs, and tests to reflect track-list-first behavior.

Acceptance Criteria

• No finance workflow hard-fails solely because holdings are missing.
• Users can persist tickers once and avoid retyping every command.
• Omitted-ticker runs are deterministic:
  • track-list mode when populated
  • global mode when empty
• No portfolio dependency remains in government-trading path.
• Tests cover empty-list, populated-list, and explicit ticker modes.

Notes

• Supersedes historical portfolio-fix context from #30.