Add a retargetable, human-readable vanity link namespace /l/<alias> that
sits alongside the untouched /share/... routes.
- New share_aliases table (workspace-scoped, UNIQUE(workspace_id, alias),
page_id nullable ON DELETE SET NULL so the address outlives its target).
- ShareAliasRepo + ShareAliasService (create / no-op / 409 reassign guard /
availability / request-time readable-target resolution through the single
existing share boundary).
- Public ShareAliasRedirectController (GET /l/:alias) issues a 302 (never 301,
the target is mutable) to the canonical /share/:key/p/:slug page; unknown /
dangling / no-longer-readable aliases serve the SPA index with no leak.
'l/:alias' excluded from the global /api prefix.
- Authenticated ShareAliasController (set/remove/availability/for-page).
- Shared ASCII-only normalize/validate util (server + client copies).
- Client: Custom address block in the share modal (live normalize + debounced
availability + copy + reassign confirmation dialog).
- Unit tests: util, repo SQL-shape, service semantics, migration/entity sanity
(server jest) + client alias util (vitest).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
