chore(ui): replace emoji with Material icons across chat UI (#944)

* chore(ui): replace emoji with Material icons across chat UI

Removes emoji glyphs and swaps them for real Material icons / plain text:

- ToolSchemaRegistry: iconEmoji String -> ImageVector icon for all ~35 tools;
  summaryPrefix emoji stripped (terminal keeps '$ '); consumer renders Icon().
- ToolBubble: collapsed summary now shows Icon(config.icon) instead of an emoji
  Text prefix; web-search url drops the link emoji; warning badge uses
  Icons.Filled.Warning instead of a '⚠' Text glyph.
- ChatBubble SelfImprovementReviewCard: 🛠/🧠 String -> Build/Psychology Icon.
- ChatViewModel / ChatWsEventReducer: drop ⚠️/✅ prefixes from user-facing
  status/error messages (severity already conveyed by color/styling).
- SubagentInspectionSheet: ✅/🔄/❌/⭕ status markers -> CheckCircle/Autorenew/
  Cancel/RadioButtonUnchecked (tinted); ElectricBolt section headers ->
  FormatListBulleted + Groups.
- strings.xml (en/zh/ko): drop '✓' from the Copied label.

ktlint clean; compileDebugKotlin SUCCESSFUL. Remaining chat files
(ToolViewBuilder, ChatComposer, MessageCards, ChatReactions, ComposerToolbar,
FullBleedAgentMessage) tracked in follow-up commits on this branch.

* test: align unit tests with emoji-free summary + status messages

composeToolSummaryLines dropped the emoji parameter and no longer prepends
an emoji glyph to the collapsed summary line, so update ToolSummaryLinesTest
call sites + expected strings accordingly.

SlashCommandDispatchRpcTest asserted the old '⚠️ /cmd: ...' error messages;
those prefixes were removed in the UI cleanup, so drop them from the
expected strings.

ChatWsEventReducerTest emoji usages are model-output fixtures, not assertions
on changed code paths — left untouched.

app/src/main/java/com/m57/hermescontrol/data/ws/WsEvent.kt

@@ -143,7 +143,7 @@ sealed class WsEvent {
     /**
      * Self-improvement background review summary event.
      * Emitted when background review patches a skill or saves a memory.
-     * Payload: `{ text: "💾 Self-improvement review: ..." }`
+     * Payload: `{ text: "Self-improvement review: ..." }`
      */
     data class ReviewSummary(
         val text: String,