test(runner): close the DEV-2498 audit gaps the browser can reach

[danielzytohoc]

What

Five spec-only E2E additions in runner/e2e/, one per browser-reachable gap from the DEV-2498 coverage audit. No product code changes. All deterministic — the Sandpack bundler is aborted and every API call is stubbed — and green in a local pnpm e2e run against the vite preview (full suite: 161 passed, 0 failed).

The five tests, mapped to tickets

Gap	Ticket	Test
G4	DEV-2500 (f)	files-drop.spec.ts — Replace on a colliding drop overwrites in place, and adds no copy. Replace and Cancel both leave exactly one /notes.md row, so the test reads the active editor after Replace and requires second. Verified by mutation: temporarily asserting first fails, so the content read is the discriminator.
G7	DEV-2500 (g)	files-drop.spec.ts — a drop on a folder row lands inside that folder. Mirror of the pointer-off-a-row test: same event sequence, but it stays on the /src row and completes the drop — /src/notes.md appears, root /notes.md does not.
G6	DEV-2499 (reachability)	new blank-starter.spec.ts — the Create tile links to ?example=blank and lands on the blank file set (not the react showcase); the blank entry opens with startRows and none of registerAllModules/contextMenu/sample data; the picker lists all three Blank templates first (first-row asserted, so a reorder fails).
G5	DEV-2501 / parent My-demos surface	all-demos.spec.ts — a demo the MCP created shows up on your own list. A scope=mine row with forked_from: "mcp:react" and created_by = the caller renders as a first-class owned card: Rename and Delete in the kebab, Open → /edit/:id. stubDemos grew an extraMine parameter so the owner-filter head-counts on the all scope stay untouched.
G9	DEV-2507 (share surface)	description-markdown.spec.ts — a shared demo's description renders as markdown for its reader. The file's assertions all ran on /edit/:id; this one hits /share/:id anonymously (ShareRoute's user is always null) and asserts a real <strong> in Box info with no literal **filters**.

Verification

• pnpm e2e e2e/files-drop.spec.ts e2e/blank-starter.spec.ts e2e/all-demos.spec.ts e2e/description-markdown.spec.ts — 32 passed.
• Full pnpm e2e — 161 passed, 124 skipped (gated live/matrix), 0 failed.
• Mutation spot-check on the Replace test: inverting the content assertion fails the test, then restored.

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Note

Low Risk
Adds E2E tests only; no runtime, auth, or data-path changes.

Overview
Spec-only Playwright coverage for five browser-reachable gaps from the DEV-2498 audit — no product changes. Everything is deterministic (stubbed APIs, aborted Sandpack).

Files drop (files-drop.spec.ts): adds tests that a drop on a folder row lands under that folder (mirror of the existing pointer-off-row case), and that Replace on a name collision overwrites file content in place (editor shows second, not first) without creating a -1 copy.

Blank starter (new blank-starter.spec.ts): Create links to ?example=blank and loads the blank file set; blank example has minimal grid setup without showcase plugins/data; example picker lists the three Blank templates first.

My demos / MCP (all-demos.spec.ts): stubDemos accepts optional extraMine rows for scope=mine without affecting Everyone (3) on the all list; new test that a demo with forked_from: "mcp:react" appears as a first-class owned card (Rename/Delete, Open → /edit/:id).

Share markdown (description-markdown.spec.ts): anonymous /share/:id renders description markdown in Box info (e.g. <strong>), not raw ** syntax — complementing existing /edit tests.

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