webui: keep parameter ranges inside what the engine accepts

[CryptVenture]

Split out of #374 as requested: ranges that let the UI produce hard errors. The dead controls, the default overrides, the missing groups and the label text are separate PRs.

The problem

Nine minimums sat below the engine's own guard, so a legal-looking slider position produced a 500 instead of a clamped value.

Group / control	Was	Now	Guard
qwen3_tts.temperature	min 0.0	0.05	src/models/qwen3_tts/session.cpp:68 — "temperature must be positive when sampling"
confucius4_tts.temperature	min 0.0	0.05	src/models/confucius4_tts/request.cpp:62
confucius4_tts.top_p	min 0.0	0.01	src/models/confucius4_tts/request.cpp:65 — must be in (0, 1]
personaplex.temperature, personaplex.text_temperature	min 0.0	0.05	positive-value parse
vevo2.temperature	min 0.0	0.05	positive-value parse
dramabox.reference_duration_sec	min 0.0	0.5	src/models/dramabox/session.cpp:149
dramabox.audio_chunk_threshold_sec, audio_chunk_duration_sec	min 0.0	1.0	same derivation, frame counts round to zero
controlfoley.guidance_scale	min 0.0	0.1	src/models/controlfoley/pipeline.cpp:176 reads it through positive_float_option, which throws at zero
controlfoley.duration_sec	min 0.1, no max	0.64 – 60.0	the range model_specs/controlfoley.json declares; below the floor the derived clip/visual/sync frame counts round to zero
midashenglm_gen.min_stop_step	min 0	1	src/models/midashenglm_gen/session.cpp:175 parses it as a positive integer

echo_tts.num_inference_steps had a maximum equal to its own default, so the control could only reduce quality; the ceiling moves to 120.

Also here

Three controls lose their default as well as their range — personaplex.text_temperature (follows temperature when unset), vevo2.temperature and vevo2.top_p (read from the checkpoint's generation config). They become blank number inputs rather than sliders pinned to a literal, for the same reason as the sibling defaults PR.

Worth flagging separately: model_specs/controlfoley.json declares guidance_scale min 0.0 while the engine throws at zero. That is a spec bug, not a UI one, and belongs to the spec series rather than this PR.

Validation

python3 -m json.tool webui/configs/model_params.json   # parses
python3 tools/check_loader_catalog_sync.py
# ok: runtime loaders, model_specs, and model_manager_v2 are in sync

Every bound above was read from the guard named beside it.

Scope

One data file, 14 controls. No code change. The generated bundle is deliberately excluded — catalog.ts inlines this file at frontend build time and the bundle is not byte-reproducible, so regenerating it in each PR of this split would make the PRs conflict; happy to send one bundle-regeneration PR once the series lands.

[CryptVenture]

Closing for now to stay inside the 3-concurrent-PR policy (see the discussion on #422). Nothing is wrong with the change and CI is green on it; I will reopen it as review slots free.