Clean up lint/LSP across gateway, Android, and desktop (alpha -> stable)

Gateway (gateway-plugin/):
- Fix interactive_setup broken imports: print helpers were imported from the
  wrong hermes module (hermes_cli.config instead of hermes_cli.cli_output) plus
  a non-existent print_code; the try/except swallowed the ImportError so
  `hermes gateway setup` for android always bailed out early.
- Fix release_scoped_lock type error (str | None passed where str required).
- Rewrite empty `except: pass` blocks as contextlib.suppress with rationale.
- Restructure two ambiguous ws_server try blocks (hello-auth, frame loop).
- Ruff cleanup: type annotations, import sorting, line wrapping, magic values
  -> named constants, `raise ... from e`, complexity. Add gateway-plugin/ruff.toml.
- Add pyrightconfig.json so the Python LSP resolves hermes-runtime imports.
- Suppress verified false positives inline (parameterized SQL, column-name
  "secrets", hermes-generated media path).

Android (app/androidApp + app/shared):
- Consolidate launcher icons into a single mipmap-anydpi (minSdk 29 >= 26) with
  the monochrome layer; clears ObsoleteSdkInt + MonochromeLauncherIcon.
- Bump core-splashscreen 1.0.1 -> 1.2.0; pin targetSdk 34 (deliberate).
- Suppress verified findings inline (LAN ws:// default, correct GCM IV usage).

Desktop (app/desktopApp):
- Move the desktop to a Java 21 runtime (org.gradle.java.home) and set the
  desktop jvmTarget to 21 (Android stays JVM 17 / minSdk 29). Fixes the startup
  UnsupportedClassVersionError and restores Markdown renderer 0.44.0.

Tooling/config:
- .pi-lens.json: disable verified-noisy heuristics (documented in docs).
- .gitleaks.toml: allowlist git-ignored false-positive paths.
- docs/18-code-review.md: full findings + verification.

Verified: ruff clean, pyright 0 errors, 64/64 gateway tests, all Kotlin tests,
Android lint 0 issues, Android installed+launched on device, desktop launches
on JDK 21.

app/shared/build.gradle.kts

@@ -36,7 +36,14 @@ kotlin {
         }
         withHostTest { }
     }
-    jvm("desktop")
+    jvm("desktop") {
+        // Desktop runs on the Java 21 runtime (see gradle.properties
+        // org.gradle.java.home); target 21 so the Markdown renderer 0.44.0
+        // (Java-21 bytecode) loads. Android keeps its JVM 17 target above.
+        compilerOptions {
+            jvmTarget.set(JvmTarget.JVM_21)
+        }
+    }
 
     sourceSets {
         // Both targets are JVM-based (androidTarget + jvm("desktop")), so