docs(phases): convert TODO L3/L4 into phases 159 (edit & resend) and 160 (tool-call budget)

TODO.md's two open items become executable phase directories under .agents/phases/todo/:

- 159_edit_and_resend_message (5 tasks): inline edit affordance on the last
  user bubble, in-place resend that truncates the replaced turn, an editable
  error turn after an oversize question, and the Playwright suite
  tests/e2e/test_edit_and_resend_message.py.
- 160_tool_budget_telemetry (5 tasks): remaining tool-call count in every
  tool result, tool calls rejected (never shown) once the budget is spent,
  the additive done.budget_exhausted flag + rounds=/cap_hit= log fields,
  the Continue researching affordance, and
  tests/e2e/test_tool_budget_telemetry.py.

No application code changed; the TODO lines are recoverable from git history.

LLM-Generated: true

TODO.md

@@ -1,3 +1 @@
 # TODO
-
-- [ ] image extraction from a PDF is throwing a 404 `https://brain.reeseapps.com/api/documents/679071cb-99f7-4c21-af46-2fa8ff916730/pages/1`