feat: add vertical flowchart block

[miguel-heygen]

Problem

Closes #558.

The catalog only had a 1920x1080 flowchart block. Vertical short-form projects targeting 1440x2560 had to either avoid the block or letterbox/stretch a landscape composition.

What this fixes

• Adds a new flowchart-vertical registry block at 1440x2560.
• Keeps the same flowchart content, ids, timeline beats, cursor interaction, and typing correction as the landscape block.
• Adds a matching registry-item.json so catalog/install flows can address the portrait block by name.
• Uses root-id selectors in the new block to avoid introducing the self attribute selector pattern.

Root cause

The existing flowchart block hard-codes landscape dimensions and geometry. A parent composition cannot override the child block's data-width, data-height, SVG viewBox, or node positions from outside the block.

Verification

Local checks

• bunx oxfmt --check registry/blocks/flowchart-vertical/flowchart-vertical.html registry/blocks/flowchart-vertical/registry-item.json
• bunx oxlint registry/blocks/flowchart-vertical/flowchart-vertical.html -> 0 files inspected by oxlint, no errors
• Direct core lint on registry/blocks/flowchart-vertical/flowchart-vertical.html -> 0 errors, 1 existing composition_file_too_large warning, 1 external script info
• bun run build:hyperframes-runtime
• bun run --filter @hyperframes/cli dev -- lint /tmp/hf-flowchart-vertical-qa -> 0 errors, 1 existing composition_file_too_large warning

Browser verification

• Created /tmp/hf-flowchart-vertical-qa embedding compositions/flowchart-vertical.html.
• Opened Studio at http://localhost:5190 with agent-browser.
• Played the timeline and captured the portrait block preview.
• Screenshot: qa-artifacts/issue-558/flowchart-vertical-3s.png
• Recording: qa-artifacts/issue-558/flowchart-vertical-playback.webm

Notes

The composition_file_too_large warning is inherited from the current catalog/linter policy for large single-file blocks. Splitting the flowchart into smaller sub-compositions would be a broader catalog refactor, so this PR keeps the new block structurally aligned with the existing flowchart item.

[jrusso1020]

LGTM — clean portrait variant for issue #558.

Quality checks:

• Root has data-composition-id="flowchart-vertical", distinct from the landscape flowchart (so both can coexist in a project)
• 1440×2560 dimensions match the registry-item.json declaration
• All 19 GSAP selectors use string concatenation (S + " #node-X"); zero template literals — passes template_literal_selector lint rule out of the box (relevant because that's the same lint rule the existing landscape flowchart block tripped per issue #559, fixed in #564)
• window.__timelines["flowchart-vertical"] = tl; registered correctly
• 12s duration matches the GSAP timeline structure (intro through fade-out)

— Review by Rames Jusso