feat(highlight): preset overhaul, categories, stats, theme colours, per-host profiles

Rules & engine:
- 22 presets (was 11): split status into okstate/warnstate/badstate, add delop,
  createop, danger, secret, level, exitcode, percent, http; status words are
  case-insensitive and cover the ✓ ✔ ✅ ✗ ✘ ✖ ❌ ⚠ symbol set
- value bands: the first number in a match picks the colour
  (percent: <20% red / 20-50% yellow / 50-80% light green / >=80% green)
- optional per-rule `caseInsensitive`, `category`, `bands`; load-time
  `refreshBuiltinRules` upgrades untouched built-in patterns in place

Settings page:
- three-way master switch `highlightMode` (all / basic / off); `basic` runs only
  the five safety+status rules and `off` empties the rule set rather than
  bypassing HighlightStream (which would drop the held tail)
- category column + grouping (`highlightGroupByCategory`), per-rule hit/duration
  stats (`highlightStats`, opt-in sink, snapshot once a second), theme-following
  colours (`highlightThemeColors`, hue-bucket mapping onto the ANSI palette),
  import/export JSON envelope, live preview through the real engine
- named rule subsets bound per host (`highlightPerHost` + `highlightProfiles`
  + `SshConnection.highlightProfileId`); empty ruleIds = every rule

Tests: new tests/hl-rules.mjs (word boundaries, case flag, negative words,
bands, import/export, preview, basic mode, categories, stats, theme colours,
profiles) + profile round-trip in tests/settings-store.mjs

tests/build-bundles.cjs

@@ -24,7 +24,9 @@ const BUNDLES = [
   // Sentry from the same library.
   { entry: 'src/main/zmodem.ts', out: 'tests/.zmodem-e2e.cjs', external: ['ssh2'] },
   // The smoke test imports the renderer engine (.ts), so it needs bundling too.
-  { entry: 'tests/hl-split-smoke.mjs', out: 'tests/.hl-split-smoke.cjs' }
+  { entry: 'tests/hl-split-smoke.mjs', out: 'tests/.hl-split-smoke.cjs' },
+  // Preset-rule assertions (word boundaries, case flag) over the same engine.
+  { entry: 'tests/hl-rules.mjs', out: 'tests/.hl-rules.cjs' }
 ]
 
 for (const { entry, out, format = 'cjs', external = [] } of BUNDLES) {