Docs: reconcile README status and test-count drift

Goal

Bring the root README back into alignment with the repository state after the recent Network normalization and Panel trigger milestones.

Audit findings

The current README contains at least two stale claims:

1. The Features section still says 627 test cases, while the latest verified workspace suite at Issue #17 completion is 677 tests.
2. The Roadmap still lists Network URL normalization as proposed/future work even though Issue #17 has now resolved and implemented URL canonicalization/redaction.

The README also contains a screenshot TODO that says styles.ts is still a placeholder. That statement is currently true in substance, because the Panel stylesheet deliberately remains minimal and real visual styling is now tracked separately in Issue #20.

Scope

Audit the README against the repository at the time of implementation and update only claims that can be established from current code, tests, ADRs, and completed issues.

At minimum:

• replace the stale test count with the verified current count,
• move Network URL normalization/redaction out of the proposed roadmap wording and describe the actual completed contract,
• preserve remaining genuinely open Network work such as response metadata if it remains unresolved,
• keep the Panel visual-styling TODO accurate until Issue #20 is complete,
• verify React, Session Import, floating trigger, and other recently completed status claims against the actual exports/implementation rather than blindly editing numbers.

Constraints

• Documentation-only unless a genuine architectural contradiction is discovered.
• Do not rewrite historical ADRs to make them prettier.
• Do not add features just to satisfy README wording.
• Do not turn this into a repository-wide documentation rewrite.
• Preserve the project's architecture terminology and links.

Verification

Verify relevant package exports/examples and run pnpm format:check plus git diff --check. Run broader tests/build only if the documentation changes affect executable examples or package metadata.

Keep the final diff focused.

Start with the root README and compare its test count, Network roadmap wording, Panel styling TODO, and recent completion claims against the repository exports, examples, ADRs, and completed issues named in the report. Verify the documented state without changing historical ADRs, then run pnpm format:check and git diff --check; done means the focused README diff matches the current implementation and preserves unresolved work accurately.