fix(lint): sentence-case audit on user-facing strings

ObsidianReviewBot flagged 49 sentence-case findings on commit
cfbceba2; an audit of every cited line classified ~47 of them as
brand-name false positives (Recraft, Magnific, Freepik, Ideogram,
ImageKit, Imgur, WebP — all product names that our local
eslint.config.mjs allowlists for `obsidianmd/ui/sentence-case`, but
the server-side bot runs the rule with the default DEFAULT_BRANDS
list which doesn't know our integrations).

Two strings were genuine violations of sentence case and are fixed
here:

- main.ts:153 — command name `'Drop gate: Reset session-remembered
  destination'` → lowercase `reset` after the colon, since "Reset"
  is not a proper noun and after-colon capitalization isn't standard
  sentence case in Obsidian's UI conventions.
- settings/settings.ts:915 — heading
  `"Drag-Drop / paste confirmation gate"` → lowercase `drop` after
  the hyphen; "Drag-drop" is one compound word, not two proper nouns.

The remaining brand-name flags are addressed via a `/skip` comment
on PR #12524 once the bot rescans this push. Plan and `/skip` draft
text live at:
context-v/plans/2026-05-10_Final-ObsidianReviewBot-Cleanup-Round.md

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

main.ts

@@ -150,7 +150,7 @@ export default class ImageGinPlugin extends Plugin {
 
         this.addCommand({
             id: 'reset-drop-gate-session',
-            name: 'Drop gate: Reset session-remembered destination',
+            name: 'Drop gate: reset session-remembered destination',
             callback: () => {
                 this.dropGateHandlers?.resetSession();
                 new Notice('Image gin: drop-gate session reset.');

src/settings/settings.ts

@@ -912,7 +912,7 @@ export class ImageGinSettingTab extends PluginSettingTab {
         }
 
         // ─── Drop Gate ──────────────────────────────────────────────
-        new Setting(containerEl).setName("Drag-Drop / paste confirmation gate").setHeading();
+        new Setting(containerEl).setName("Drag-drop / paste confirmation gate").setHeading();
         containerEl.createEl('p', {
             text: 'When enabled, every image dropped or pasted into a note opens a confirmation modal asking where it should go: vault attachments, ImageKit, or Imgur. Built for writers who handle private client imagery and want every image destination to be a deliberate decision.',
             cls: 'image-gin-settings-blurb',