[xysamuel]

Summary

This PR combines two improvements, kept in separate commits for review:

1. Clipboard shelf: an optional horizontal bottom-shelf presentation with larger image previews, per-card Send/Copy actions, filters, and the existing list/detail view.
2. Zhipu / BigModel support: correct endpoint construction for versioned API bases such as https://open.bigmodel.cn/api/coding/paas/v4, plus Coding Plan and standard BigModel presets.

Clipboard changes

• Add persistent Cards / List switching; cards are the default when no preference exists.
• Position the shelf within the display's visible frame, avoiding the Dock/menu bar; restore ordinary launcher geometry when leaving it. Detached windows remain user-sized.
• Give image cards up to 384 px of width, minimal padding, uncropped aspect-preserving images, 768 px thumbnails, and up to 1440 px full previews.
• Add visible Send and Copy buttons to each card. Send uses the existing paste-to-previous-application path: it does not press Return or submit a message. Copy targets that card, shows feedback, and leaves the shelf open.
• Support all/pinned/text/link/image/file filters, search, full preview and keyboard navigation. Retain clear confirmation and preserve pinned records.
• Lazy-load thumbnails with size-aware, bounded caches. Render copied text literally; do not execute HTML or fetch remote link previews.
• Include English / Simplified Chinese strings, light/dark styles, responsive narrow-window layouts, focus indicators and button labels.

The new layout request is restricted to the bundled clipboard extension. Existing one-argument thumbnail callers keep the 96 px default, and image access retains the existing clipboard permission check.

Model endpoint fix

Previously, only a /v1 suffix was recognized, so a Zhipu /v4 base became /v4/v1/chat/completions.

The builder now:

• Preserves complete /chat/completions or /messages endpoints.
• Recognizes terminal version segments such as /v1, /v3, /v4, and /v1beta, appending only the API method path.
• Retains /v1/... fallback for unversioned bases, including existing DeepSeek, OpenRouter and Anthropic-compatible providers.
• Trims surrounding whitespace/newlines and trailing slashes.
• Adds Zhipu Coding Plan and standard BigModel presets.

Validation performed locally

• ./scripts/test-model-endpoints.sh — 25 checks passed, compiling the production endpoint builder; no network calls, model keys or persisted settings.
• ./scripts/test-clipboard.sh — 1200×466 light fixture; 57 PASS checks (including shelf geometry).
• ./scripts/test-clipboard.sh 1200 466 --dark — 57 PASS checks.
• ./scripts/test-clipboard.sh 420 268 — 56 PASS checks.
• ./scripts/test-clipboard.sh 420 268 --dark — 56 PASS checks.
• ./scripts/bundle.sh release --universal — arm64 + x86_64 development bundle.
• SPOTCAT_CHANNEL=release ./scripts/bundle.sh release --universal — arm64 + x86_64 release-channel bundle, matching the existing CI build command.
• codesign --verify --deep --strict on both resulting ad-hoc-signed bundles.
• git diff --check and candidate-file scan for credentials, private keys and personal absolute paths.

WebKit checks use synthetic in-memory records and mocked clipboard APIs. They cover card/list persistence, large-image geometry, clicked-card action targeting, duplicate prevention, feedback/error paths, keyboard navigation, filters, preview/search races, injection safety, clear confirmation, and 1,000-entry rendering. They do not exercise real cross-application paste or live provider authentication. Physical multi-monitor placement, Accessibility permission prompts and real cross-app paste remain manual integration checks; no claim of those being covered by the fixtures is intended.

Endpoint regression checks are also added to the existing CI workflow. Reproduction details and bridge behavior are documented in docs/clipboard-shelf.md. Screenshots are not attached to this submission.

Scope / privacy

No API keys, clipboard history, model settings, local signing identities/certificates, application backups or build artifacts are included. This PR does not change signing/install/release scripts, application identifiers, or update behavior. Local-only certificate/installation changes have deliberately been excluded.