M9: collaboration polish: unique ids for styles, variables and comments; live text carets (#107)

- Styles, variables, collections, modes and comment threads created in a live
  session take ids from the creator's client space (figcraft_doc::ids: a
  number from the node id allocator, client_id << 32 | counter); outside a
  session ids are made exactly as before. The server refuses a new entry in
  another connected client's space (removed entries can be put back by undo),
  keeps removed entries in its saved state, and starts client ids above every
  space used by any kind of id.
- Others' text carets and selected characters show on the canvas in their
  colour at the glyph positions, with their name above the caret (no blinking,
  no frames of their own). Typing in a layer someone else is typing in says so
  (toast and tag); collab.peers reports who types where.
- Toasts wrap at a readable width.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

docs/collaboration-parity.md

@@ -1,18 +1,18 @@
 # Collaboration parity
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-11 · **Change:** minor (wording: live sessions, the browser joins them, invite links open the app; numbers unchanged) · **Target:** Figma Design (desktop app 126.10.7)
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-11 · **Change:** minor (wording: live sessions, the browser joins them, invite links open the app; collaboration polish: collision-free ids, remote text carets; numbers unchanged) · **Target:** Figma Design (desktop app 126.10.7)
 
 Figma is multiplayer first; FigCraft is local first. **Ready ~12% (estimated):** comments and version
 history work inside one file; the real-time collaboration core landed in #103 (sync model,
 server ordering, client reconciliation, convergence tests), and live sessions (preview) let
-several apps co-edit a file hosted by one desktop app, joined from the desktop app or the browser
-([`collab-protocol.md`](collab-protocol.md)). Remaining: 55–110 h
+several apps co-edit a file hosted by one desktop app, joined from the desktop app or the browser,
+with others' cursors, selections and text carets shown live ([`collab-protocol.md`](collab-protocol.md)). Remaining: 55–110 h
 (multiplayer 45–90 h, shared libraries 10–20 h), plus branching 8–15 h.
 
 | Feature | Figma | FigCraft | Hours |
 |---|---|---|---|
-| Real-time co-editing | yes | **core built, no networking** (#103): client-scoped ids, per-property change sets with fractional positions, server ordering and validation, optimistic clients, binary messages; randomized multi-client convergence tests over real commands. Live sessions over the network landed (`crates/collab-net`): the WebSocket transport (keep-alive, size and rate limits, reconnect with backoff), hosting from the app (this machine or the local network) with invite links, live cursors with name tags, selections, avatars and follow, `collab.*` commands. Document sync between apps works over them (the host's server orders every batch; guests open the host's file as a new tab). Undo is per person (only your own steps, others' later writes left alone), refused edits roll back with a toast, and a reconnect resumes as the same client with what it missed (or a snapshot) and sends what was made offline. The browser build joins (same messages through the browser's WebSocket API); `figcraft://` invite links open the desktop app and join. Left: standalone server with TLS | 25–55 |
-| Live cursors, selections, viewports; follow / observation mode; spotlight | yes | **partial**: cursors with name tags, selections, avatars and follow in live sessions; no spotlight | 8–15 |
+| Real-time co-editing | yes | **core built, no networking** (#103): client-scoped ids, per-property change sets with fractional positions, server ordering and validation, optimistic clients, binary messages; randomized multi-client convergence tests over real commands. Live sessions over the network landed (`crates/collab-net`): the WebSocket transport (keep-alive, size and rate limits, reconnect with backoff), hosting from the app (this machine or the local network) with invite links, live cursors with name tags, selections, avatars and follow, `collab.*` commands. Document sync between apps works over them (the host's server orders every batch; guests open the host's file as a new tab). Undo is per person (only your own steps, others' later writes left alone), refused edits roll back with a toast, and a reconnect resumes as the same client with what it missed (or a snapshot) and sends what was made offline. The browser build joins (same messages through the browser's WebSocket API); `figcraft://` invite links open the desktop app and join. Styles, variables, collections, modes and comments made in a session take ids from their creator's space (the server checks it), so concurrent creations all survive; modes, per-mode values and replies inside one entry still resolve last-writer-wins. Left: standalone server with TLS | 25–55 |
+| Live cursors, selections, viewports; follow / observation mode; spotlight | yes | **partial, in live sessions**: named cursors, selection outlines, avatars, follow (click an avatar), others' text carets and selected characters with their names, a note when two people type in one layer; no spotlight | 8–15 |
 | Cursor chat, audio, high-fives | yes | no | 4–8 |
 | Share links, permissions (view / edit), teams and projects | yes | no | 8–17 |
 | Comments: pins on frames and layers, threads, reactions, @mentions, resolve, unread, search and filters, links, in the presenter | yes (shared) | **done, local**: stored in the file, your name from Preferences | (shared once multiplayer lands) |
@@ -25,6 +25,7 @@ several apps co-edit a file hosted by one desktop app, joined from the desktop a
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-11 | minor | Collaboration wording after the collaboration polish: styles, variables, collections, modes and comments created in a live session take ids from their creator's id space (concurrent creations no longer overwrite each other; the server checks it), others' text carets and selections show on the canvas, and typing in a layer someone else is typing in says so; percentages unchanged |
 | 2026-10-11 | minor | Wording only: live sessions (#104), then the browser joining them and `figcraft://` invite links opening the desktop app; percentages and hours unchanged until the next re-measure |
 | 2026-10-10 | minor | Merged main after #101–#103: WASM plugins (plugins area 0% → 35% breadth, 20% ready; ecosystem 5% → 20%) and the multiplayer core without networking (multiplayer 5% → 15% breadth, 5% ready; collaboration 8% → 12%); menu breadth 97.5% → 98.5% (200/203); ready for real work ~46% → ~47%; full parity 420–790 h → 390–745 h; beta 210–380 h → 200–365 h. Fixed the stated weight sums (areas 1–16 sum to 94, total 113; percentages were already computed with those) |
 | 2026-10-10 | major | Created from the 2026-10-10 re-measure |