fix: route embed details with explicit provider

[mariusvniekerk]

Embed detail surfaces now carry provider in the route contract and pass it directly into the workspace sidebar. This avoids classifying self-hosted GitLab instances by hostname text.

[mariusvniekerk]

This change is part of the following stack:

• Add embed-targetable workspace surfaces and project/worktree registry #258
  • fix: preserve project provider identity #261
    • fix: route embed details with explicit provider #262 ◀
      • fix: preserve nested repo paths in embeds #263
        • refactor: isolate workspace embed shell #264

_{Change managed by git-spice.}

[roborev-ci]

roborev: Combined Review (80405db)

Medium risk: legacy embedded detail URLs may no longer route to the detail surface.

Medium

• frontend/src/lib/stores/router.svelte.ts:219
  The parser now only accepts /workspaces/embed/detail/:provider/:type/..., so existing embedded detail URLs using the previous /workspaces/embed/detail/:type/... shape fall through to the generic workspaces page instead of rendering the embedded detail surface. Keep a legacy matcher that parses the old route shape and infers the provider as before, or redirect legacy routes to the new provider-explicit form during a transition.

• frontend/src/lib/stores/router.test.ts:212
  This user-visible embedded workspace detail routing change only has router unit coverage; there is no e2e/API+SQLite coverage proving the explicit provider reaches the detail sidebar workflow. Add an e2e test that navigates to a provider-explicit embed detail route, preferably for GitLab/non-github.com, and asserts the rendered sidebar/API flow uses that provider.

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Synthesized from 3 reviews (agents: codex, gemini | types: default, security)

[roborev-ci]

roborev: Combined Review (dfb5e5f)

No Medium, High, or Critical findings were reported.

All provided reviews either found no issues or contained no findings to merge.

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Synthesized from 3 reviews (agents: codex, gemini | types: default, security)

[roborev-ci]

roborev: Combined Review (291bdf5)

No Medium, High, or Critical findings were reported.

All review agents found no actionable issues at Medium severity or above.

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Synthesized from 3 reviews (agents: codex, gemini | types: default, security)

[roborev-ci]

roborev: Combined Review (c5120e9)

Regression found: legacy GitHub Enterprise embed links can now resolve with the wrong provider.

High

• frontend/src/lib/stores/router.svelte.ts:111
  Legacy embed detail URLs now infer gitlab for every host except exactly github.com. This regresses prior behavior, where hosts were treated as GitHub unless they contained gitlab, so legacy GitHub Enterprise URLs like ghe.example.com now issue detail requests with the wrong provider.

  Fix: Match the previous heuristic:

  return platformHost.toLowerCase().includes("gitlab") ? "gitlab" : "github";

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Synthesized from 3 reviews (agents: codex, gemini | types: default, security)