theme(849): unify presets behind one palette template + bespoke AMOLED status colors (#852)

* refactor(theme): unify all presets behind one palette template

* docs(theme): update THEMES.md and AGENTS.md for the palette template

* fix(theme): restore per-preset error slot contrast, merge StatusColors into HermesStatusColors

- onErrorContainer becomes an explicit per-preset field (was derived from
  onError — same-color pairs in Gruvbox/Catppuccin light made error text
  invisible; 6 screens render this slot)
- Default dark + AMOLED onError -> White (were <3:1 on their error color)
- drop StatusColors + statusColorsOf mapper; PaletteColors.status is typed
  HermesStatusColors directly (identical field lists, pure copy ceremony)
- ThemePalette getters now by lazy; schemeFor/statusFor accessors;
  requireNotNull on the default-theme fallback (DefaultTheme is FULL)
- resolvers internal for testability

* test(theme): contrast, mode-validation, and fallback contract tests

- every shipped mode's onError/error + onErrorContainer/errorContainer
  pair meets >= 3:1 WCAG contrast (kills the error-slot regression class)
- ThemeMode init validation rejects illegal palette combinations
- AMOLED darkOnly contract + light-mode fallback to Default light

* refactor(theme): Catppuccin — named swatches from the official palette spec

Hex values verified identical (zero color drift): repeated colors (Crust,
Surface0/1, Base, Text...) now live once as named swatches matching
catppuccin.com; bespoke light primary container tints stay local.
Mocha/Latte pair unchanged.

* refactor(theme): Gruvbox — authentic bright/faded accent scheme with named swatches

Redesign per gruvbox spec: bright accents on dark bg0-bg4, faded accents
on light bg0-bg4 (correct contrast play for light mode). Named swatches,
single Gray shared across modes. Dark error pair fixed for >= 3:1
(onErrorContainer -> DarkFg1 cream, was bright red on Bg3 = 1.87:1).

* feat(theme): replace default preset with Slate — modern slate blues + teal accents

The brand default (voltage purple/amber) becomes Slate: bright teal/blue
accents on dark bg0-bg4, faded variants on light bg0-bg4. Named swatches,
single neutral gray shared across modes. Slate is also the fallback for
darkOnly/lightOnly presets (AMOLED light mode).

* feat(theme): add Nord preset — Polar Night/Snow Storm surfaces, Frost/Aurora accents

Nord's single accent set is reused across both modes (pastel accents stay
light, so on* colors use Polar Night dark text in both modes — documented
in-file). Surface ladder shares outer tiers (Nord ships 4 dark + 3 light
tones for 5 tiers). Dark error pair fixed for >= 3:1 (onErrorContainer ->
Nord6, was Nord11 on Nord2 = 2.0:1). Wired into ThemePreset, the settings
picker, and docs; default label now reads Default (Slate).

* refactor(theme): Monochrome + AMOLED — pure grayscale ramp, true-black AMOLED variant

Monochrome: every swatch R=G=B, roles by lightness only (status colors
included — documented trade-off: pair with icons/labels). AMOLED: dark-only
true-black variant (pure #000000, OLED pixels off; #121212 baseline of
Monochrome doesn't do that), containers collapse where nothing darker
exists. Both ship maximum-contrast grayscale pairs (12.8:1+ on error
slots).

* chore(theme): drop Neon Noir, finalize docs + picker label

- remove NeonNoirScheme.kt + ThemePreset.NEON_NOIR everywhere (dispatcher,
  picker, strings EN/KO, tests, AGENTS.md, THEMES.md) — 6 presets remain:
  Default, Monochrome, Gruvbox, Catppuccin, AMOLED, Nord
- picker label for the default preset is now plain 'Default'
- THEMES.md: preset conventions section (named swatches, bright/faded
  split, grayscale-status caveat, contrast test gate) + verify step runs
  testDebugUnitTest

* fix(theme): make drawer icon colors visibly follow the active preset

Selected icon now tints with the theme's primary accent (teal for Slate,
orange for Gruvbox, mauve for Catppuccin, frost-blue for Nord) instead of
onPrimaryContainer — the new presets' containers are all dark gray with
near-white text, so the selected row looked identical across themes.
Unselected icon/text colors pinned explicitly to onSurfaceVariant.

* chore(ui): remove lightning emoji from the app

- drawer title + About name: '⚡ Hermes' -> 'Hermes' (EN + KO)
- skill markers (chat self-improvement badge, memory graph): ⚡ -> 🛠
- in-progress indicators (subagent inspection): ⚡ -> 🔄

---------

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

app/src/main/res/values/strings.xml

@@ -61,7 +61,7 @@
     <string name="billing_topup">Top-up</string>
 
     <!-- Navigation & Drawer -->
-    <string name="nav_drawer_title">⚡ Hermes</string>
+    <string name="nav_drawer_title">Hermes</string>
     <string name="nav_drawer_subtitle">AI Agent Control</string>
     <string name="nav_drawer_section_converse">Converse</string>
     <string name="nav_drawer_section_automate">Automate</string>
@@ -163,7 +163,7 @@
     <string name="settings_delay_100ms">100 ms</string>
     <string name="settings_action_test_connection">Test Connection</string>
     <string name="settings_sec_about">About</string>
-    <string name="settings_about_app_name">⚡ Hermes Mobile</string>
+    <string name="settings_about_app_name">Hermes Mobile</string>
     <string name="settings_about_version">Version</string>
     <string name="settings_about_build">Build</string>
     <string name="settings_about_debug">Debug</string>
@@ -196,12 +196,12 @@
     <string name="settings_item_use_dynamic_colors">Dynamic Colors</string>
     <string name="settings_desc_use_dynamic_colors">Derive scheme from wallpaper (Android 12+)</string>
     <string name="settings_item_theme_preset">Preset Theme</string>
-    <string name="theme_preset_default">Default (Voltage Purple)</string>
+    <string name="theme_preset_default">Default</string>
     <string name="theme_preset_monochrome">Monochrome</string>
     <string name="theme_preset_gruvbox">Gruvbox</string>
     <string name="theme_preset_catppuccin">Catppuccin</string>
     <string name="theme_preset_amoled">AMOLED Black (Dark only)</string>
-    <string name="theme_preset_neon_noir">Neon Noir</string>
+    <string name="theme_preset_nord">Nord</string>
 
     <!-- Language -->
     <string name="settings_item_language">Language</string>