fix(android): A2/A3/A4 — APK build doc, dead refs, modal hit targets

A2: docs/ANDROID.md — remove stale "permanent fix to come" note;
    clarify --lib is the canonical command; root-cause the upstream
    cargo-apk bug. SESSION_HANDOFF.md closes the open item.

A3: Remove dead CARD_PLAN.md references from four source module
    doc comments (theme/importer.rs, theme/plugin.rs, assets/mod.rs,
    assets/svg_loader.rs). Also fix stale "future picker UI" language
    in plugin.rs (picker shipped in Phase 7).

A4: ui_modal.rs spawn_modal_button — add min_height: Val::Px(48.0)
    so every modal action button meets Material's 48 dp touch target
    minimum. Modal button height was 42 px (2×SPACE_3 + TYPE_BODY_LG);
    now clamped to 48 px minimum. Cards at 40 dp on 360 dp phones are
    layout-constrained (7 columns) and cannot be widened.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/ANDROID.md

@@ -143,16 +143,18 @@ After the APK is signed cargo-apk panics with:
 thread 'main' panicked: Bin is not compatible with Cdylib
 ```
 
-This happens AFTER the APK is on disk and signed. cargo-apk is
-trying to also wrap the desktop `[[bin]]` target. The APK is still
-valid. Work around with `--lib`:
+This happens AFTER the APK is on disk and signed. cargo-apk tries to
+also wrap the desktop `[[bin]]` target alongside the `[lib]`. The APK
+is valid — the panic is cosmetic. **Always use `--lib`**, which is the
+canonical build command (see `CLAUDE.md §15.1`):
 
 ```bash
-cargo apk build -p solitaire_app --target x86_64-linux-android --lib
+cargo apk build -p solitaire_app --lib
 ```
 
-(Permanent fix to come — likely a `[[bin]] required-features = ["desktop"]`
-gate so cargo-apk skips the bin target on Android.)
+Root cause: upstream cargo-apk bug — it does not skip `[[bin]]` targets
+when building for Android. No in-repo fix is possible; `--lib` is the
+accepted workaround.
 
 ---