chore(audience-sample): trim unused packages and engine modules from SampleApp

Drops 30 of 39 manifest.json entries that the SampleApp does not use.
Verified by grepping the SampleApp source, the SampleApp scene, and
the Audience SDK runtime for any reference to each removed module or
package.

Removed packages:
- com.unity.textmeshpro: no TMP_Text or TMPro references
- com.unity.timeline: no PlayableDirector or TimelineAsset references
- com.unity.ugui: SampleApp uses UI Toolkit, no Canvas references
- com.unity.visualscripting: no ScriptMachine or graph references

Removed engine modules:
- ai, animation, assetbundle, cloth, director, imageconversion,
  particlesystem, physics, physics2d, screencapture, terrain,
  terrainphysics, tilemap, ui, umbra, unityanalytics, vehicles, video,
  vr, wind, xr: no runtime references in SampleApp or audience SDK
- unitywebrequestassetbundle, unitywebrequestaudio,
  unitywebrequesttexture, unitywebrequestwww: SDK uses
  System.Net.Http.HttpClient, not UnityWebRequest variants

Kept (verified used or required):
- com.immutable.audience: the SDK
- com.unity.test-framework: test runner
- com.unity.modules.androidjni: Android plugin compatibility
- com.unity.modules.audio: AudioListener present in SampleApp scene
- com.unity.modules.imgui: test runner overlay
- com.unity.modules.jsonserialize: defensive
- com.unity.modules.uielements: UI Toolkit, primary UI surface
- com.unity.modules.unitywebrequest: defensive (test framework)

Expected impact:
- Smaller IL2CPP and Mono player binaries.
- Faster IL2CPP compile and Bee/Tundra build phases on every cell.
- Faster project init (less to load, fewer InitializeOnLoad hooks).
- Per-frame UI Toolkit cost on llvmpipe is unchanged; that is targeted
  separately by PR #765's log-pane suppression.

Risk: a build link error on a platform that needs a removed module
shows immediately in CI; revert is one-line.

Author: ImmutableJeffrey

examples/audience/Packages/manifest.json

@@ -2,40 +2,11 @@
   "dependencies": {
     "com.immutable.audience": "file:../../../src/Packages/Audience",
     "com.unity.test-framework": "1.4.5",
-    "com.unity.textmeshpro": "3.0.6",
-    "com.unity.timeline": "1.6.5",
-    "com.unity.ugui": "1.0.0",
-    "com.unity.visualscripting": "1.9.4",
-    "com.unity.modules.ai": "1.0.0",
     "com.unity.modules.androidjni": "1.0.0",
-    "com.unity.modules.animation": "1.0.0",
-    "com.unity.modules.assetbundle": "1.0.0",
     "com.unity.modules.audio": "1.0.0",
-    "com.unity.modules.cloth": "1.0.0",
-    "com.unity.modules.director": "1.0.0",
-    "com.unity.modules.imageconversion": "1.0.0",
     "com.unity.modules.imgui": "1.0.0",
     "com.unity.modules.jsonserialize": "1.0.0",
-    "com.unity.modules.particlesystem": "1.0.0",
-    "com.unity.modules.physics": "1.0.0",
-    "com.unity.modules.physics2d": "1.0.0",
-    "com.unity.modules.screencapture": "1.0.0",
-    "com.unity.modules.terrain": "1.0.0",
-    "com.unity.modules.terrainphysics": "1.0.0",
-    "com.unity.modules.tilemap": "1.0.0",
-    "com.unity.modules.ui": "1.0.0",
     "com.unity.modules.uielements": "1.0.0",
-    "com.unity.modules.umbra": "1.0.0",
-    "com.unity.modules.unityanalytics": "1.0.0",
-    "com.unity.modules.unitywebrequest": "1.0.0",
-    "com.unity.modules.unitywebrequestassetbundle": "1.0.0",
-    "com.unity.modules.unitywebrequestaudio": "1.0.0",
-    "com.unity.modules.unitywebrequesttexture": "1.0.0",
-    "com.unity.modules.unitywebrequestwww": "1.0.0",
-    "com.unity.modules.vehicles": "1.0.0",
-    "com.unity.modules.video": "1.0.0",
-    "com.unity.modules.vr": "1.0.0",
-    "com.unity.modules.wind": "1.0.0",
-    "com.unity.modules.xr": "1.0.0"
+    "com.unity.modules.unitywebrequest": "1.0.0"
   }
 }