feat(config): redo config tab — lazy list, full-coverage search, per-field reset (#898)

- LazyColumn + precomputed flat dot-path value map: O(1) lookups, only
  visible fields compose (829 live leaves on a real config)
- Search now matches keys, labels, descriptions, categories, CURRENT
  values and select options; non-schema ('Other') paths are searchable too.
  Result count + category chip per hit while searching
- Per-field reset-to-default icon; clear-to-blank honoring schema
  'clearable'; searchable dropdown honoring schema 'searchable'
  (select-all-free fresh filter, exact-match commits on blur)
- Number/object/list editors keep local text state: intermediate typing
  ('0.') no longer drops keystrokes; objects/lists edit as multi-line JSON
  with validation
- Honor backend searchable/clearable schema flags (SchemaField model)
- Category reset now previews default values immediately

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

app/src/test/java/com/m57/hermescontrol/ui/config/ConfigFormDataTest.kt

@@ -0,0 +1,181 @@
+package com.m57.hermescontrol.ui.config
+
+import com.m57.hermescontrol.data.model.SchemaField
+import kotlinx.serialization.json.JsonArray
+import kotlinx.serialization.json.JsonNull
+import kotlinx.serialization.json.JsonObject
+import kotlinx.serialization.json.JsonPrimitive
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+/**
+ * Pure-logic tests for the config form's data layer: flattening the nested
+ * config response into dot-paths, "Other" path discovery, and the search
+ * matcher (which must cover keys, labels, descriptions, categories, CURRENT
+ * VALUES and select options — the value/option coverage was missing before
+ * the redo).
+ */
+class ConfigFormDataTest {
+    // ── flattenConfig ──────────────────────────────────────────────────────
+
+    @Test
+    fun `flattenConfig walks nested objects into dot paths`() {
+        val nested =
+            JsonObject(
+                mapOf(
+                    "model" to JsonPrimitive("gpt-4o"),
+                    "terminal" to
+                        JsonObject(
+                            mapOf(
+                                "backend" to JsonPrimitive("local"),
+                                "timeout" to JsonPrimitive(30),
+                            ),
+                        ),
+                ),
+            )
+        val flat = flattenConfig(nested)
+        assertEquals(
+            mapOf(
+                "model" to JsonPrimitive("gpt-4o"),
+                "terminal.backend" to JsonPrimitive("local"),
+                "terminal.timeout" to JsonPrimitive(30),
+            ),
+            flat,
+        )
+    }
+
+    @Test
+    fun `flattenConfig keeps arrays and nulls as leaf values`() {
+        val nested =
+            JsonObject(
+                mapOf(
+                    "toolsets" to JsonArray(listOf(JsonPrimitive("terminal"), JsonPrimitive("web"))),
+                    "unset" to JsonNull,
+                ),
+            )
+        val flat = flattenConfig(nested)
+        assertEquals(2, flat.size)
+        assertEquals(
+            JsonArray(listOf(JsonPrimitive("terminal"), JsonPrimitive("web"))),
+            flat["toolsets"],
+        )
+        assertEquals(JsonNull, flat["unset"])
+    }
+
+    @Test
+    fun `flattenConfig on already-flat map is identity`() {
+        val flat = mapOf("a.b" to JsonPrimitive(1), "c" to JsonPrimitive("x"))
+        assertEquals(flat, flattenConfig(flat))
+    }
+
+    // ── isCoveredBySchema ──────────────────────────────────────────────────
+
+    @Test
+    fun `isCoveredBySchema matches exact key and ancestors`() {
+        val schema = setOf("tts.provider", "model")
+        assertTrue(isCoveredBySchema("tts.provider", schema))
+        assertTrue(isCoveredBySchema("model", schema))
+        // Ancestor relationship: key below a schema key is covered
+        assertTrue(isCoveredBySchema("tts.provider.x", schema))
+        assertFalse(isCoveredBySchema("tts.other", schema))
+        // Prefix boundary: "tts.providers" must NOT match "tts.provider"
+        assertFalse(isCoveredBySchema("tts.providers.custom", schema))
+    }
+
+    // ── collectUncoveredPaths ──────────────────────────────────────────────
+
+    @Test
+    fun `collectUncoveredPaths finds only schema-orphaned leaves`() {
+        val flat =
+            mapOf(
+                "model" to JsonPrimitive("x"),
+                "tts.provider" to JsonPrimitive("edge"),
+                "tts.providers.custom.voice" to JsonPrimitive("amy"),
+                "dashboard.host" to JsonPrimitive("0.0.0.0"),
+            )
+        val schema = setOf("model", "tts.provider")
+        assertEquals(
+            listOf("dashboard.host", "tts.providers.custom.voice"),
+            collectUncoveredPaths(flat, schema),
+        )
+    }
+
+    // ── rowMatchesQuery ────────────────────────────────────────────────────
+
+    private fun row(
+        key: String,
+        field: SchemaField?,
+        value: kotlinx.serialization.json.JsonElement? = null,
+    ) = ConfigRow(key = key, field = field, value = value)
+
+    @Test
+    fun `search matches dot key and human label`() {
+        val r = row("model_context_length", SchemaField(type = "number"), JsonPrimitive(8192))
+        assertTrue(rowMatchesQuery(r, "model_context"))
+        assertTrue(rowMatchesQuery(r, "context length"))
+    }
+
+    @Test
+    fun `search matches description and category`() {
+        val r =
+            row(
+                "stt.local.model",
+                SchemaField(type = "select", description = "Local faster-whisper model size", category = "stt"),
+            )
+        assertTrue(rowMatchesQuery(r, "whisper"))
+        assertTrue(rowMatchesQuery(r, "stt"))
+    }
+
+    @Test
+    fun `search matches current value`() {
+        val r = row("model", SchemaField(type = "string"), JsonPrimitive("anthropic/claude-sonnet-4.6"))
+        assertTrue(rowMatchesQuery(r, "claude-sonnet"))
+        assertFalse(rowMatchesQuery(r, "gpt-4o"))
+    }
+
+    @Test
+    fun `search matches select options`() {
+        val r =
+            row(
+                "terminal.backend",
+                SchemaField(type = "select", options = listOf("local", "docker", "ssh", "modal", "daytona")),
+                JsonPrimitive("local"),
+            )
+        assertTrue(rowMatchesQuery(r, "daytona"))
+        assertTrue(rowMatchesQuery(r, "docker"))
+    }
+
+    @Test
+    fun `search matches uncovered paths by key and value`() {
+        val r = row("plugins.myplugin.enabled", field = null, value = JsonPrimitive("true"))
+        assertTrue(rowMatchesQuery(r, "myplugin"))
+        assertTrue(rowMatchesQuery(r, "true"))
+    }
+
+    @Test
+    fun `search is case-insensitive and blank query matches all`() {
+        val r = row("Model", SchemaField(type = "string"), JsonPrimitive("OpenAI"))
+        assertTrue(rowMatchesQuery(r, "openai"))
+        assertTrue(rowMatchesQuery(r, "MODEL"))
+        assertTrue(rowMatchesQuery(r, ""))
+        assertTrue(rowMatchesQuery(r, "   "))
+    }
+
+    @Test
+    fun `search does not match unrelated keys`() {
+        val r = row("memory.provider", SchemaField(type = "select"), JsonPrimitive("builtin"))
+        assertFalse(rowMatchesQuery(r, "terminal"))
+    }
+
+    // ── jsonText ───────────────────────────────────────────────────────────
+
+    @Test
+    fun `jsonText renders primitives, objects and arrays`() {
+        assertEquals("42", jsonText(JsonPrimitive(42)))
+        assertEquals("hello", jsonText(JsonPrimitive("hello")))
+        assertEquals("{\"a\":1}", jsonText(JsonObject(mapOf("a" to JsonPrimitive(1)))))
+        assertEquals("[1,2]", jsonText(JsonArray(listOf(JsonPrimitive(1), JsonPrimitive(2)))))
+    }
+}