test: wait for all quorum member connections

[thepastaclaw]

Issue being fixed or feature implemented

The first mine_quorum() in feature_llmq_connections.py could advance into DKG phase 2 before every selected member had established its required authenticated quorum connections. The failed CI logs in #7466 show two members announcing their contributions before their relay links were ready; those contributions never left their originators, so the test remained below five received contributions until its existing 120-second sanitizer-adjusted wait expired.

The race came from wait_for_quorum_connections() returning from inside its masternode loop after the first matching member was ready. This PR fixes #7466.

Tracker: thepastaclaw/tracker#2090

What was done?

• Check every visible matching DKG session instead of returning after the first ready member.
• Require the expected number of matching quorum-member sessions, while continuing to ignore supplied nonmembers that correctly have no session.
• Keep advancing mocktime through the existing retry callback until the complete connection predicate is satisfied.
• Add framework unit coverage for an incomplete member, all members ready, and a missing expected member session.

How Has This Been Tested?

• PYTHONPATH=test/functional python3 -m unittest test_framework.test_framework.TestFrameworkQuorumConnections
• python3 test/functional/feature_llmq_connections.py --randomseed=3108379943187254370 --portseed=62090 ... (the retained failing CI seed)
• Three additional consecutive feature_llmq_connections.py runs with distinct seeds and port seeds
• test/lint/lint-python.py
• test/lint/lint-whitespace.py
• python3 -m py_compile test/functional/test_framework/test_framework.py test/functional/test_runner.py
• git diff --check upstream/develop...HEAD

The focused functional validation used a local macOS debug build. The original failure was observed in Linux UBSan CI; this PR remains draft for the repository's sanitizer and full functional-test coverage.

Breaking Changes

None.

Checklist

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated relevant unit/integration/functional/e2e tests
• I have made corresponding changes to the documentation
• I have assigned this pull request to a milestone (for repository code-owners and collaborators only)

[thepastaclaw]

✅ Final review complete — no blockers (commit 1666123)

[thepastaclaw]

Final validation — Codex + Sonnet

The final implementation correctly checks every visible matching DKG session and requires the expected number of member sessions before reporting readiness. All production callers pass the corresponding expected member count, and the focused tests cover incomplete connections, complete readiness, and a missing session; no in-scope defect remains.

Review provenance

• Codex reviewers: gpt-5.6-sol — general (completed), gpt-5.6-sol — dash-core-commit-history (completed)
• Verifier: gpt-5.6-sol — final-verifier (fallback)
• Sonnet reviewers: claude-sonnet-5 — general (failed), claude-sonnet-5 — dash-core-commit-history (completed), claude-sonnet-5 — general (completed)

Note: GitHub does not allow PastaClaw to submit an approval or request changes on their own PR, so the canonical verifier result is transported as a COMMENT review.