feat(system-ai): auto-load models on open + suitability hints (v0.13.1)

Two operator-felt papercuts on the editor:

  * Models only appeared after a manual Refresh click. Now the
    editor calls `_refreshModels()` from initState (post-frame)
    so chips populate immediately. Provider switch also re-fires
    the refresh because endpoint / model set changes too.

  * Operator had no signal which model is suitable. Tiny models
    fail at instruction following; huge models stall on a
    laptop. Adds a heuristic suitability rating (parses
    parameter count from common names like `gemma3:4b`,
    `llama3.2:70b`; falls back to family hints for OpenAI /
    Claude). Each chip now carries:
       - a coloured leading dot (green=balanced, orange=small
         or large, red=huge, grey=unknown)
       - a star icon for the hand-curated "tested with F∆I"
         allowlist (gemma3:4b, llama3.2:3b, qwen2.5-coder:7b,
         gpt-4o-mini, claude-haiku-4-5, …)
       - a tooltip ("balanced", "huge — likely too slow on a
         laptop", …)
    Sorting also moves recommended → balanced → others to the
    front so the operator's eye lands on green first.

  * Compact legend below the chip wrap explains the colour
    code in place — no lookup needed.

Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

pubspec.yaml

@@ -1,7 +1,7 @@
 name: fai_studio
 description: "F∆I Studio — desktop GUI for the F∆I hub"
 publish_to: 'none'
-version: 0.13.0
+version: 0.13.1
 
 environment:
   sdk: ^3.11.0-200.1.beta