ui: multi-image composer, prompt-tools under prompt, --ui-open flags

- Composer accepts up to /api/config maxInputImages attachments;
  gpt-image-2 /edits receives every entry, other generators index 0
- Fix spelling / fix typos / undo move from the send row to #prompt-tools
  directly under the prompt box; new UI Control Placement rule recorded
  in .cursorrules and AGENTS.md (controls live next to the input they
  act on)
- --ui-open / --ui-no-open control the browser tab on --ui start
  (default: open when interactive, skip under systemd)
- gpt2 guidance localStorage key bumped to gpt2GuidanceTextV2 so stale
  copies of the replaced default text retire
- docs/provider-onboarding.md: researched onboarding notes for candidate
  providers (Seedream, Reve, Luma, Qwen, MiniMax, Runway)

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: ernop

.cursorrules

@@ -35,6 +35,11 @@
 - A fallback is allowed only when the user has explicitly specified that exact behavior as a product requirement. Document it at the call site and validate that it cannot select unrelated data.
 - Declared input defaults chosen before an operation starts are not failure fallbacks. Once an operation starts, never replace failed output with different output.
 
+## UI Control Placement
+- Controls live next to the input they act on. A button, toggle, or helper that edits/fixes/clears a specific field sits immediately down/right of that field — not in a distant shared toolbar.
+- Example: prompt "fix typos" / "fix spelling" / "undo fix" sit under `#prompt`; Generate (whole-form submit) stays in the send row.
+- Same rule for future field-scoped actions (reset, clear, validate, rewrite-this-field).
+
 ## Universal Image Prompt Defaults
 - When writing or rewriting image-generation prompts, default to clear, bright, full normal daytime lighting unless the user explicitly asks for dark, night, low-key, gloomy, or murky output.
 - Explicitly avoid dim, murky, grimy, muddy, gloomy, shadow-choked, underexposed, dusk-like, night-like, or dark results.

AGENTS.md

@@ -244,6 +244,11 @@ public class RunOptions
         /// Port for --ui. The server binds 127.0.0.1 only.
         public int UiPort { get; set; } = 5960;
 
+        /// Whether --ui should open a browser tab on start.
+        /// null = default (open when interactive; skip under systemd).
+        /// true/false = force via --ui-open / --ui-no-open.
+        public bool? UiOpenBrowser { get; set; }
+
         /// Master switch for popping finished images/contact-sheets open in the
         /// system default viewer. Defaults to false: runs are headless and just
         /// save to disk. Set with --open-images. Drives
@@ -332,6 +337,12 @@ public static RunOptions Parse(string[] args)
                     case "--ui-port":
                         o.UiPort = int.Parse(args[++i]);
                         break;
+                    case "--ui-open":
+                        o.UiOpenBrowser = true;
+                        break;
+                    case "--ui-no-open":
+                        o.UiOpenBrowser = false;
+                        break;
                     case "--repl-size":
                         o.ReplSize = args[++i];
                         break;
@@ -505,6 +516,8 @@ private static void PrintUsage()
             Console.WriteLine("  --quick-test      Like --fast plus: save every streamed partial PNG and open each one in the default viewer as it arrives (implies --open-images). Still asks y/n/custom per prompt unless combined with --auto.");
             Console.WriteLine("  --ui              Start the local web UI (browser control panel): paste an image + prompt, fan out to selected generators (gpt-image-2 edit, grok-web pro, grok-api), watch results fill in live. Binds 127.0.0.1 only.");
             Console.WriteLine("  --ui-port N       Port for --ui (default 5960).");
+            Console.WriteLine("  --ui-open         Force opening a browser tab when --ui starts (default for interactive runs; unused under systemd unless set).");
+            Console.WriteLine("  --ui-no-open      Never open a browser tab when --ui starts (default under systemd so restarts don't pile up tabs).");
             Console.WriteLine("  --repl            Interactive prompt-by-prompt REPL. Prompts fire asynchronously (up to --repl-concurrency at a time); NO viewer pops. Commands: :help :size :quality :gens :status :wait :edit :retry :quit.");
             Console.WriteLine("  --repl-size WxH       REPL session default size for gpt-image-2 (default 2048x2048). Change at runtime with :size WxH.");
             Console.WriteLine("  --repl-quality L      REPL session default quality: low|medium|high (default high). Change at runtime with :quality <L>.");