fix: resolve 9 confirmed bugs — crashes, data races, logic errors, and resource leaks

[cherryroots]

Summary

• Crashes/panics: NaN timestamp and chunk-index panic in VideoToBase64Images; slice-bounds panic in SplitParagraph when code fence has no trailing newline
• Resource leaks: HTTP response body leak in hasher.getFile when status is non-200 (TCP connection pool exhaustion)
• Data races: resolution written in concurrent goroutines in draw command; msgCount/hashCount incremented without mutex in hash_server; blocking time.Sleep in AfterFunc callback in flushBuffer
• Logic errors: playerTax returns negative value when player bets > 10% of money; Streamer.Stop() deadlocks if goroutine has already exited (unbuffered done channel); consolidation loop exits on REINFORCE without checking remaining facts for contradictions
• Silent data loss: sqlite-vec ANN MATCH+k= queries apply user_id filter after the k-nearest scan, silently returning 0 results when other users' facts crowd the result set

Test Plan

• go test ./... -timeout 60s — all packages pass
• go build -race -o voltgpt — builds clean with race detector
• Each fix has a companion test added before the fix (TDD)
• Pre-existing ffmpeg-go@v0.5.0 race in Silent() confirmed on main — not introduced by this PR

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