fix(AppShell): wire up <colour> control hint for script textboxes

[alexwarren]

Summary

• Part of Editor: several v5 .aslx control hints not wired through to AppShell (freetext, min/max/increment, nullable, width, ...) #2116, and closes out the issue's full tag list.
• <colour> was fully dead (2 uses: @failed's fallback-script text in red, a // comment's text in green, both CoreEditorScriptsScripts.aslx) - same family as fix(AppShell): honor multiline/expand script control hints, auto-size code view #2115's <multiline/>/<expand/> fix (a script-control hint, not a property-panel one).
• While wiring it up, found that @failed///'s controls also declare <multiline/>/<expand/> (the tags fix(AppShell): honor multiline/expand script control hints, auto-size code view #2115 fixed) but never actually got that fix. fix(AppShell): honor multiline/expand script control hints, auto-size code view #2115 only patched the "expression" controltype's textbox simple editor rendering path (used by e.g. Print's message); @failed/// use controltype=textbox directly, a separate branch in ScriptEditor.svelte that still rendered a plain single-line <input> regardless of the hints. ScriptControlData.Multiline/Expand were already read unconditionally in BuildScriptControlData - the gap was purely on the frontend, in a code path fix(AppShell): honor multiline/expand script control hints, auto-size code view #2115 didn't touch. Coloring a still-single-line box for what's meant to be multi-line fallback-script/comment text would have been a confusing half-fix, so this PR completes multiline/expand for that controltype too, in the same branch, alongside colour.
• Adds Colour to ScriptControlData, and mirrors the existing simple-editor multiline/expand rendering (growing textarea) into the direct "textbox"/"richtext" controlType branch of ScriptEditor.svelte, with the colour applied as an inline color style on both the textarea and the (still-used-by-other-controls) plain input.

Test plan

• dotnet build --configuration Release
• dotnet test --configuration Release (all passing)
• npm run check / npm run lint in src/AppShell (clean)
• node tests/e2e/find-affected-tests.mjs + ran the relevant flagged scripts (verify-appshell-code-view, verify-appshell-script-label-stacks-below, verify-appshell-scripteditor-row-buttons, verify-appshell-scripteditor-selection-toolbar) against a local dev server - all pass.
• Manual check in-browser: added a // Comment script command and confirmed via computed style it's now a <textarea> (rows: 1, auto-growing height) with color: green (previously a plain <input> with no color). Typed multi-line text into it and confirmed the box grows to fit, staying green throughout.

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