docs: update 0.34 features, fix stale refs, expand globals

[Chemaclass]

Summary

Doc audit follow-up. Four focused commits, one per finding.

• docs(cli): document 0.34 features (watch, tags, TAP output) — add watch subcommand, --watch, --tag, --exclude-tag, --output tap to command-line.md (previously only in release blog post).
• docs(cli): update stale version refs to 0.34.1 — replace hardcoded 0.32.0 / 0.28.0 samples in command-line.md.
• docs(globals): add missing helpers and cross-links — document bashunit::caller_line, bashunit::print_line, clarify bashunit::is_command_available, cross-link custom-assert helpers (assertion_passed, assertion_failed, fail) and test doubles.
• docs(config): document BASHUNIT_OUTPUT_FORMAT for TAP — add env var to configuration.md.

Test plan

• npm run docs:build succeeds locally
• npm run docs:dev renders new sections without broken anchors
• Internal link #watch / #output-format / #watch-mode resolve

[github-actions]

✅ Contributor Report

User: @Chemaclass
Status: Trusted contributor (whitelisted)

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