a3e3a905ac
- Defer MCP server discovery off the first-paint critical path for UI sessions; tools and slash commands stream in through the existing live-refresh channel once each server connects (non-UI modes keep the blocking path). ~290ms off first paint with MCP servers configured. - Build the model catalog's canonical-equivalence index lazily on first read instead of eagerly in the ModelRegistry constructor. A default interactive launch never reads it pre-paint, moving the ~210ms build (over ~3,200 models) off the critical path: ~244ms (~16%) off cold boot. - Memoize per-session read summaries (tree-sitter parse) on the content hash of the freshly-read bytes; the file is still read fresh each call so results stay correct. Repeat same-file summary read 17ms -> 2.4ms. - Reuse the Markdown subtree across streaming reveal ticks, memoize grapheme counting, and stop re-highlighting finalized thinking blocks. - Attribute the previously-unlabeled synchronous boot region in the PI_TIMING table and add a bench:guard boot-regression target.