Rename remaining Gittensory brand-prose in browser extension runtime UI

[JSONbored]

Problem: Issue #5329 (rename the two browser extension manifests, build artifacts, and hardcoded API origin) shipped in #5509 — its literal 4 deliverables are correct: both manifest.json files, auth.js's DEFAULT_API_ORIGIN, build-extension.mjs's zip filename, and extension.tsx's download link/copy all now say "LoopOver" consistently.

However, both extensions' own runtime UI files still contain literal "Gittensory" brand-prose text that was not touched by #5329 (out of that issue's literal scope/boundaries) and isn't covered by any other filed sub-issue of the LoopOver Rebrand Migration epic (#4761). This means the extensions' toolbar name says "LoopOver" but the actual on-page UI a user sees still says "Gittensory":

• apps/gittensory-extension/content.js (the maintainer overlay injected onto GitHub PR pages — the primary visible surface of the extension): visible overlay header label, and an aria-label referencing "Refresh Gittensory context". CSS class names (gittensory-overlay__header, gittensory-overlay__refresh) and the data-gittensory-pr-context dataset attribute are internal identifiers, not brand-prose — leave those alone, matching the existing "don't rename GITTENSORY_*-prefixed identifier names, only brand-prose values" convention already established elsewhere in this codebase (see apps/gittensory-extension/auth.js's GITTENSORY_SESSION_PATTERN).
• apps/gittensory-extension/options.html: page title, an h1 heading, and body copy referencing "the Gittensory app".
• apps/gittensory-miner-extension/opportunity-badge.js (visible badge label injected onto GitHub issue pages). Leave the CSS class names (gittensory-miner-opportunity-badge__header etc.) alone — same identifier-vs-prose distinction as above.
• apps/gittensory-miner-extension/options.html: page title and an h1 heading. This file also has a legitimate directory-path reference (apps/gittensory-extension/) inside body copy — leave that one alone, it's a real source path, not brand prose (consistent with how Rename the two browser extension manifests, build artifacts, and hardcoded API origin #5329 deliberately left directory-path references untouched).

Area: Extensions / Frontend

Proposal: Rename only the literal brand-prose display text (titles, headings, visible labels, aria-labels, body copy) in these 4 files from "Gittensory" to "LoopOver", matching this rebrand's established capitalization convention ("LoopOver" for display/product-name text — confirmed via README.md, CONTRIBUTING.md, CODE_OF_CONDUCT.md, and other already-merged rebrand PRs).

Deliverables:

• Updated visible text in content.js, both options.html files, and opportunity-badge.js.

Acceptance criteria:

• Both extensions' runtime UI (overlay panel, options pages, opportunity badge) show "LoopOver" everywhere a user would see brand text, with no old-brand strings remaining.
• CSS class names, dataset attributes, and the real apps/gittensory-extension/ directory-path reference are left untouched.

Boundaries:

• Do NOT rename CSS class names, dataset attribute names, or directory-path references.
• Leave every reference to the separate gittensor network's own domain/name untouched.

---

Part of #4761.

[linear-code]

JSO-3829