Document mTLS and automatic client-certificate reloading across all client languages

[xShinnRyuu]

Summary

Document mutual TLS (mTLS) and automatic client-certificate reloading across every valkey-glide client language. Today only Java has a doc section under how-to/security/tls; the other languages either ship the API without docs or have the API in flight.

Current state

• Java: shipped in valkey-io/valkey-glide#6386 (merged). Docs section proposed in valkey-io/valkey-glide-docs#271 covers all three Java modes (in-memory PEM, path-based with default reload, path-based with custom interval) plus loadClientCertificateFromFile and loadClientKeyFromFile. Python, Node.js, Go, C#, and PHP tabs in that PR are placeholders (:::note[Coming soon]:::).
• Python: byte-based mTLS already shipped in valkey-io/valkey-glide#5124 and valkey-io/valkey-glide#5093. Automatic path-based reload is in flight in valkey-io/valkey-glide#6596.
• Go: mTLS with automatic reload is in flight in valkey-io/valkey-glide#6384.
• Node.js: mTLS with automatic reload is in flight in valkey-io/valkey-glide#6383. Earlier byte-based mTLS work in valkey-io/valkey-glide#5404.
• C#, PHP: no shipped mTLS API yet.

Related merged core work: reload cadence is core-driven, so a single core default (currently 300 seconds) applies to every language that opts into path-based reload.

What this issue tracks

Backfill the placeholder tabs in src/content/docs/how-to/security/tls.mdx (or open follow-up PRs) so every language with a shipped API has real code in the mTLS section. Each per-language backfill should include:

1. In-memory (byte-based) example, loaded once at connection time.
2. Path-based example that opts into the core-driven periodic reload (default cadence, no custom interval).
3. Path-based example with an explicit reload interval, if the language exposes that knob.
4. Any per-language file-loader helper (mirroring Java's loadClientCertificateFromFile / loadClientKeyFromFile).
5. The mTLS-scoped pitfalls already documented for Java (file permissions, sub-second/non-positive interval rejection, path/bytes exclusivity, use_tls=True still required).

Suggested order of backfill, driven by shipped-API readiness:

• Python: byte-based today, path-based reload when #6596 merges.
• Go: when #6384 merges.
• Node.js: when #6383 merges.
• Java: land valkey-io/valkey-glide-docs#271 first as the reference shape.
• C#, PHP: hold as Coming soon until an API ships upstream.

References

• valkey-io/valkey-glide-docs#271: Java mTLS docs section, sets the shape.
• valkey-io/valkey-glide#6386: core + Java mTLS with reload (merged).
• valkey-io/valkey-glide#6384: Go mTLS with reload (in review).
• valkey-io/valkey-glide#6383: Node.js mTLS with reload (in review).
• valkey-io/valkey-glide#6596: Python automatic mTLS reload (in review).
• valkey-io/valkey-glide#5124: Python byte-based mTLS (merged).
• valkey-io/valkey-glide#5093: initial mTLS parameters (merged).
• valkey-io/valkey-glide#5404: earlier Node.js mTLS work.