feat(#445): full Models tab parity — settings, aux tasks, MOA config (#458)

* feat(#445): full Models tab — settings panel, aux tasks, MOA config, model assignment

Main features added:
- Model Settings card at top of screen with main model, aux tasks, MOA summary
- Main model assignment via /api/model/set with expensive model confirm flow
- Auxiliary tasks dialog with per-task model override and reset-all
- MOA config dialog with preset management and reference/aggregator model picker
- Model picker dialog reused for main model, aux tasks, and MOA slot selection
- Kept existing provider browse + pin/unpin/search

New data models: AuxiliaryModelsResponse, MoaConfigResponse,
ModelAssignmentRequest/Response
New API endpoints: GET /api/model/auxiliary, GET/PUT /api/model/moa,
POST /api/model/set

* test(#445): add aux + MOA mock endpoints to E2eIntegrationTest

testModelOptionsSelection_success was failing because the ViewModel's init
block now calls getAuxiliaryModels() and getMoaConfig() which weren't mocked.
Added proper mock returns + imports for the new types.

* fix(#445): correct mock endpoint name in E2eIntegrationTest

- getMoaConfig -> getMoaModels (matches API service method name)
- Add explicit type parameter Response.success<MoaConfigResponse>
  to fix Kotlin type inference

* fix(#445): add missing main param to AuxiliaryModelsResponse mock

AuxiliaryModelsResponse requires a MainModelAssignment for its
'main' field. Added the parameter with a dummy value and the
corresponding import.

* fix(#445): update toast assertion in test to match new message format

ViewModel now produces 'Successfully set profile model to ronia'
instead of the old 'Successfully set model to ronia'.

* fix(#445): remove top padding from Models tab LazyColumn

Top inset already provided by HermesScaffold; double padding was chunky next to TopAppBar.

* fix(#445): remove double-stacked top padding on Models tab LazyColumn

HermesScaffold's Box already applies padding(paddingValues) to
offset content below the TopAppBar. The LazyColumn was re-applying
it on the modifier, doubling the top gap. Keep the modifier clean
(.fillMaxSize() only) — the Box handles the offset.

* refactor(#445): inline loadModelOptions into loadAll

loadAll() was just delegating to loadModelOptions() with no extra
logic. Consolidate into a single method to remove the redundancy.

---------

Co-authored-by: M57 <hy4ri@users.noreply.github.com>

app/src/main/java/com/m57/hermescontrol/data/model/ModelAssignment.kt

@@ -0,0 +1,64 @@
+package com.m57.hermescontrol.data.model
+
+data class AuxiliaryTaskAssignment(
+    val task: String,
+    val provider: String,
+    val model: String,
+    val base_url: String? = null,
+)
+
+data class AuxiliaryModelsResponse(
+    val tasks: List<AuxiliaryTaskAssignment>,
+    val main: MainModelAssignment,
+)
+
+data class MainModelAssignment(
+    val provider: String,
+    val model: String,
+)
+
+data class MoaModelSlot(
+    val provider: String,
+    val model: String,
+)
+
+data class MoaConfigPreset(
+    val reference_models: List<MoaModelSlot>,
+    val aggregator: MoaModelSlot,
+    val reference_temperature: Double = 0.7,
+    val aggregator_temperature: Double = 0.3,
+    val max_tokens: Int = 4096,
+    val enabled: Boolean = true,
+)
+
+data class MoaConfigResponse(
+    val default_preset: String = "",
+    val active_preset: String = "",
+    val presets: Map<String, MoaConfigPreset> = emptyMap(),
+    val reference_models: List<MoaModelSlot> = emptyList(),
+    val aggregator: MoaModelSlot = MoaModelSlot("", ""),
+    val reference_temperature: Double = 0.7,
+    val aggregator_temperature: Double = 0.3,
+    val max_tokens: Int = 4096,
+    val enabled: Boolean = true,
+)
+
+data class ModelAssignmentRequest(
+    val confirm_expensive_model: Boolean = false,
+    val scope: String,
+    val provider: String,
+    val model: String,
+    val base_url: String? = null,
+    val task: String? = null,
+)
+
+data class ModelAssignmentResponse(
+    val confirm_message: String? = null,
+    val confirm_required: Boolean? = null,
+    val ok: Boolean = false,
+    val scope: String? = null,
+    val provider: String? = null,
+    val model: String? = null,
+    val tasks: List<String>? = null,
+    val reset: Boolean? = null,
+)