Bind Stratum work queue items to source epochs

[Distortions81]

Summary

• Give every queued work item an immutable type and matching destructor.
• Bind items to source epochs so clean jobs and reconnects invalidate stale work.
• Replace the oldest item under the queue lock at capacity.
• Generate work from the owned item type, not mutable protocol state.
• Snapshot and validate extended-channel extranonce state inside owned jobs.

Root cause and impact

The shared queue stored untyped pointers and chose their interpretation/destructor from mutable global state. V1/V2 failover or SV2 standard/extended transitions could cast or free work as the wrong type. Mining modes and the trusted-network model are unchanged.

Related work

• Add Stratum V2 (SV2) protocol support #1553 introduced the shared V1/V2 work path.
• Consolidate shared stratum socket, wifi and clean-queue helpers #1724 added shared clean-queue helpers; this extends the lifecycle with typed ownership and epochs.
• Bound SV2 extended-channel extranonce negotiation #1854 independently hardens SV2 extranonce bounds.

CI follow-up

The first run resolved a new test component relative to symlinked test-ci/ incorrectly. ../test/components now works from both local test/ and CI.

Validation

• ESP-IDF 6.0.2 firmware and ESP32-S3 test builds passed
• Exact CI QEMU environment: 74 passed, 0 failed
• Typed destruction, source mismatch, stale epoch, capacity, clear, and timeout tests
• git diff --check

Live failover and standard/extended transitions remain desirable.

[github-actions]

Test Results

  2 files    2 suites   1s ⏱️
122 tests 122 ✅ 0 💤 0 ❌
124 runs  124 ✅ 0 💤 0 ❌

Results for commit 4f22ae2.