Implement table-driven F.O.S. lesson completion

[ToumanLin]

Problem

F.O.S. lessons and assessments can be entered and played, but valid lesson-result submissions are rejected because the server does not evaluate the configured lesson completion requirement. This prevents progress from being persisted and can leave later assessments and rewards unavailable.

Summary

• Resolve submitted lessons from the authoritative course-stage table.
• Read and evaluate the configured finish condition and score threshold.
• Persist successfully completed C1/C2 lessons.
• Preserve existing exam scoring, pending/saved result, downgrade, and reward behavior.
• Reject invalid stages, result types, and insufficient scores without granting progress.
• Preserve duplicate-claim and retry behavior.
• Add coverage for lessons, real exams, persistence, rewards, downgrade handling, and BSON relog.

Data sources

Lesson completion is derived from authoritative course tables and the submitted result. No stage-specific captured values or response snapshots are embedded in runtime code.

Testing

• dotnet build AscNet/AscNet.csproj
• dotnet run --project AscNet.Test/AscNet.Test.csproj -- --course-only

[reiserFSs]

Reviewed against 67b9b1ec794540da4a805f9b5deb2a0adca54b7f. Hold pending confirmation of the lesson-completion rule.

The project builds, --course-only passes, and GitHub reports a clean merge. No published CI checks were reported.

The actual runtime change in CourseModule.cs:44-53 treats every lesson chapter as having a completion rule and sets it clear once all configured stage IDs have saved records. It does not read the configured lesson FinishCondition/score threshold described in the PR body; those fields are not present in the inspected CourseStage schema.

The client consumes the server's chapter IsClear flag. Its stage-record presence checks and distinction between completion and maximum points do not independently establish the proposed chapter-completion formula. The added C1/C2 tests exercise the chosen formula using full-star results, rather than providing an independent oracle for it.

Please provide authoritative source or a controlled retail transition establishing the rule, and align the description/tests with that evidence. Alternatively, this needs explicit maintainer approval as a documented local policy rather than a claim of established parity.

To be clear: I have not established that a zero-star result must be rejected or that lessons require full stars. The blocker is the missing authority for the formerly unsupported chapter-clear rule, not a proven score-threshold defect. No changes were pushed during review.