Record the tmux 3.3a core minimum

[tony]

Move every page, example prerequisite and install note that states a tmux minimum to 3.3a, and add a tmux support guide that states the version rules. The libraries judge the connected daemon, compare patch letters (3.3 is below 3.3a), and refuse an older daemon before the requested operation has any effect.

• Shared and per-port content, the generated example introductions, the home quickstart prerequisites and the Julia install note now say 3.3a. The JVM "3.2a through 3.7c" range becomes "3.3a through 3.7c", and Ruby's "3.3 or newer" becomes 3.3a.
• Each workspace compatibility page and the Python, Go and Rust MCP entry pages say that a daemon older than 3.3a is refused before any effect, and link the new guide.
• The new guides/tmux-support page covers daemon versus client version checks, absent endpoints, replacement daemons, raw commands, batches, MCP and workspace entry points, the standalone -V and -h diagnostics, and the built-in command assumption.
• A new check (site/test/tmux-minimum.test.ts) requires every "tmux X or newer", "tmux X+" and "tmux X through Y" statement to name 3.3a.
• Left alone on purpose: the tmux 3.2a manual and C reference archive, example runs recorded on 3.2a and 3.7c, tmux facts such as the release that added a hook, and staged port guides and API data under site/src/data. Those come from pinned port revisions and change when each port publishes its own floor.

Validation (Node 26.5.1, pnpm 12.7.0, local; pnpm test:medium was not usable because its ten-second budget was exceeded on a loaded host, so its components ran separately):

• Vitest for api-model, theme and site without the outer suites passes; the site run needed two test updates (guides card count, and the manual-link requirement the new guide satisfies).
• pnpm run type-check reports zero errors. pnpm run --recursive lint and oxlint scripts report only existing warnings. check-api-links, check-nav, gen-mentions --check (Ruby and Lua guides staged from source first), gen-shell-ports --check and gen-brand-css --check pass.
• Deliberate break: restoring one "tmux 3.2a or newer" line in topics/traversal.md makes the new check fail naming that file; restoring the fix passes (docs/deliberate-break-floor-gate.log in the evidence folder).

Not run: the assembled-site build and publication audit (pnpm test:publication), which need the port checkouts and run in hosted CI.

Closes #146.