Luix v1.5.0 - Per-file framework detection & parity improvements

Active-framework detection + status-bar picker

Every Lua / Luau file now has an active framework, picked per file
in this priority order:

1. Explicit override — the new luix.activeFramework setting
   (default auto). Set to react / roact / fusion / vide to
   force everything everywhere.
2. In-file require(…) — first match wins, in
   roact → vide → fusion → react order (Roact tested first because
   its name contains "react").
3. In-file factory call — alias of the first
   e(...) / New "..." / create "..." etc. → its framework.
4. Workspace fallback — at activation Luix samples up to 25
   indexed files and uses the most-represented framework as the
   tie-breaker for brand-new files.
5. None — no UI signal → snippets and completions stay quiet
   (same gate the existing looksLikeUIFile policy used).

A new status-bar item on the right ($(symbol-namespace) Luix: Vide) shows the current pick with a tooltip explaining where it
came from ("detected from require(…) import", "set by
luix.activeFramework", etc.). Click it to open a quickpick of
Auto, React, Roact, Fusion, Vide; the choice writes
luix.activeFramework to workspace settings. The picker is also
available via the command palette as
Luix: Set active framework….

Vide parens form — Vide.create("Frame", { … })

Vide accepts both create "Frame" { … } and
create("Frame", { … }) / Vide.create("Frame", { … }). Until
1.5.0 Luix only recognised the curried shape — the parens form
silently fell out of every detector, so prop completions, hover
docs, and call-tree inlay hints all stopped firing inside it.

• New recognizedCallShapes?: CallShape[] on FrameworkSpec. Vide
  registers both "parens" and "curried", so its aliases now land
  in both partition buckets.
• getAliasPartition() iterates recognizedCallShapes (defaulting
  to [callShape] for backward compatibility), so other frameworks
  behave exactly as before.
• Vide.create added to Vide's aliases.
• findAllCreateElementCallsImpl's parens regex now captures the
  matched alias. When the alias is also in the curried bucket
  (Vide), the props brace doubles as the inline-children container —
  Vide.create("Frame", { Child(...) }) parses with Child(...)
  as a child, not as a stray prop.

Three new tests cover the cases (findEnclosingPropsCall,
findAllCreateElementCalls nested-tree, findEnclosingFactoryStringArg).

Thank you to @Zyntion for the idea!

Snippet / scaffold parity across all four frameworks

With per-file gating in place, every framework gets the same
snippet matrix without polluting the dropdown for the others:

• Roact in the scaffold quickpick — Explorer right-click → New
  component now lists Roact alongside React / Fusion / Vide.
  Template mirrors React's but uses Roact.createElement and drops
  the React.ReactNode return annotation.
• Element snippets — Fusion (n*), Vide (c*), and Roact (r*)
  now have the same 11-snippet baseline React (e*) always had:
  Frame, ScrollingFrame, TextLabel, TextButton, ImageLabel,
  ImageButton, UIListLayout, UIGridLayout, UIPadding, UICorner,
  UIStroke. Bodies use each framework's idiomatic call shape and
  event syntax ([OnEvent "Activated"] for Fusion, plain
  Activated = function() … end for Vide).
• Function-component scaffolds — rfc (React), new rofc
  (Roact), new nfc (Fusion), new vfc (Vide). Each is gated to
  its framework — typing rfc in a Vide file no longer surfaces a
  React scaffold.
• Event-handler shorthand snippets — reactEvent (React),
  new roactEvent (Roact), new onEvent (Fusion), new videEvent
  (Vide). Each emits the right syntax for its framework — Fusion
  gets [OnEvent "Activated"], Vide gets bare Activated = function() … end, etc.
• State-primitive snippets — new for both Fusion (value,
  computed, spring, tween, observer, forKeys,
  forValues, forPairs) and Vide (source, derive, effect,
  cleanup, untrack, batch, show, switch, indexes,
  values). Each gated to its framework.

Computed-key fast-paths for all event-bearing frameworks

The [React.Event.X|] / [React.Change.X|] autocomplete used to
be hard-coded to the React prefix. Extended to:

• Roact — [Roact.Event.X|] / [Roact.Change.X|] (identical
  regex shape, just the React|Roact alternation).
• Fusion — [OnEvent "X|"] / [OnChange "X|"] / [Out "X|"]
  (the quoted-string shape Fusion uses). Property choice lists are
  pulled from the resolved class the same way the React fast-path
  does.

The dynamic computed-key starter snippets (React.Event /
React.Change choice-list entries shown inside an empty [|])
now emit the right shape for the active framework:
Roact.Event / Roact.Change for Roact files,
OnEvent / OnChange / Out for Fusion files. Vide files don't
get any computed-key starters because events are plain prop keys
there (no […] shape exists).

Setting

• luix.activeFramework — "auto" (default) /
  "react" / "roact" / "fusion" / "vide". Documented in the
  Settings UI with the full precedence ladder.

Files changed

src/frameworks.ts (CallShape, recognizedCallShapes, Vide aliases,
partition logic), src/parser.ts (capturing alias, inline-children
on parens), src/activeFramework.ts (new), src/statusBar.ts
(new), src/extension.ts (status bar + picker + workspace
fallback wiring), src/completion.ts (per-framework fast-paths +
active-framework gating), src/elementSnippets.ts (per-framework
gating, 27 new element snippets, 18 new state snippets, 3 new
scaffolds, 3 new event shorthands), src/scaffolds.ts (Roact
template + quickpick entry), src/test/extension.test.ts (fork's
3 Vide-parens tests + updated VIDE_PARTITION), package.json (new
setting, new command, version 1.4.5 → 1.5.0).