Document Photon 2.1.1 model support

[vikhyat]

Purpose

Document the customer-facing Photon capabilities shipped in Moondream 2.1.1.

Changes

• add Gemma 4 26B-A4B, Qwen3-ASR, and Parakeet TDT to the local model matrix
• generalize the transcription guide across all four released speech checkpoints
• document model-specific translation, language, prompt, sampling, and timestamp behavior
• update overview and quickstart links that described speech support as Whisper-only

Validation

• npm run typecheck
• npm run build
• all changed Python examples parsed successfully
• all literal md.photon(...) model IDs verified against the production Moondream 2.1.1 registry
• generated transcription, local inference, and overview pages inspected
• adversarial self-review completed with no remaining findings

Deployment impact

Documentation-only. This updates the existing local inference and transcription pages without changing navigation or site configuration.

This PR is intentionally left open for customer-facing review.