Move pending TODO work into GitHub Issues with acceptance criteria and
upstream blockers. Keep TODO as a short entry point and preserve implemented
behavior and invariants in maintained guides. Mark the provider descriptor
as a proposal with pinned verification evidence.

Require agents to reconcile affected documentation and issue progress in
every change without a user reminder, including direct commits to main.
Add documentation impact to the PR template and guard against rebuilding
a duplicate task inventory in TODO.

Documentation impact:
Update README, the documentation index, usage, cost history, translations,
provider descriptor, development workflow, and AGENTS instructions. Historical
research remains unchanged. No application behavior changes.

Verification:
- make check passed: 823 QML tests, 3 desktop-style QML tests, 39 Python tests,
  QML lint, ShellCheck, static checks, and AppStream validation.
- make package passed; all five translation catalogs compiled.
- Five focused documentation tests and descriptor/parity checks passed.
- Changed Markdown local links and anchors resolve; packaged README targets
  exist and historical research and screenshots are unchanged.
- Independent migration review confirmed all pending topics are preserved.

Refs #167, #168, #169, #170, #171, #172, #173, #174, #175, #176.