feat(memory): open existing inline session references

[KinomotoMio]

What this opens up

When a Memory already contains a session ID in inline code, Obelisk can now turn that existing trace into a direct reading path. For example, codex:<uuid> becomes interactive only when the local database confirms that the exact session exists.

There is no new Markdown syntax and nothing for agents to learn or rewrite.

What changed

• Collect complete inline-code values from Memory Markdown as bounded candidates.
• Exclude fenced code blocks before lookup.
• Resolve candidates with a batched exact-ID query against the App's sessions table.
• Turn only confirmed matches into internal session buttons.
• Display each confirmed session's title and expose its exact ID through the App's existing native hover convention; untitled sessions fall back to the full ID.
• Keep unknown IDs and ordinary inline code exactly as they were.
• Reuse the existing session-link styling and icon from the Memory header.
• Open confirmed sessions through the Vue Router without leaving Obelisk.

Boundary

After discussing the ownership boundary, this PR deliberately does not introduce an obelisk:// protocol or document a new agent-facing convention. Core and the published Obelisk skill are unchanged.

The App does not parse UUIDs or assume a Codex-specific shape. A value becomes interactive only when it exactly matches a real sessions.id, which keeps the behavior provider-neutral and avoids accidental format rules.

Existing Memory files are not migrated or edited.

Validation

Passed:

• npm test — 298 tests
• npm run typecheck
• npm run lint — no errors; 4 pre-existing unused-variable warnings
• cd app && npm run test:electron:memory-links
• cd app && npm run test:electron

The Electron Memory test exercises the production renderer build and confirms exact DB resolution, title-first labels, UUID hover text, untitled fallbacks, accessible labels, provider-neutral IDs, unknown and ordinary inline code, fenced-code exclusion, reused styling, and in-App navigation.

Closes #10