Add complete capture examples for all language ports

[tony]

The capture example now includes F#, Kotlin, Scala, Lua and Ruby. Each port gets a standalone program with imports, explicit build files and pinned setup, bounded waiting, and cleanup of its private tmux server. The root page links to all thirteen variants. The C++ page also explains that the single-file executable needs no separate header.

The F# setup restores the NuGet package matching the library lockfile. The JVM build files include memory settings needed to compile the pinned library. A new scripts/check-capture-prose.py runner extracts and executes the displayed files and setup without adding a prelude.

Verification

• All five programs ran on Linux with tmux 3.2a and 3.7c. Missing-import and missing-output controls failed visibly; no socket directories remained after success or failure.
• All five displayed setup recipes passed in fresh directories: Ruby 4.0.7, Lua 5.5.1 with luv 1.52.1-0, .NET SDK 10.0.302, Kotlin 2.4.10 and Scala 3.9.0 on JDK 25.0.3. Revisions, file hashes and native check results are recorded in the capture fixture.
• All fourteen new files match their native bytes in rendered HTML, Copy buttons, Markdown and LLM output. Fresh-browser checks passed at 1440px and 390px; mobile drawers close with Escape, pages have no horizontal overflow, and search finds all five variants.
• The outer site check passed in 51 seconds; the focused complete-example suite passed all 46 checks after the final F# error-reporting change.

Native execution is a separate verification step from the routine renderer tests. WRITING.md documents how to repeat it.