Mark all milestones complete; remove obsolete bootstrap-prompt docs

All planned milestones (M0-M10) are done -- PROGRESS.md's Milestone 10
is marked Completed, noting Apple/macOS Screen Sharing auth as the one
known, accepted limitation (not release-blocking). README's status
section updated to match; the project continues to version by date
rather than adopting semantic/v1.0-style versioning.

Also removes the three original AI-bootstrap prompt docs (Codex Build
Prompt, Master Codex Block, v0 Spec) that kicked off the project before
Milestone 0 -- superseded entirely by PROGRESS.md's actual history, and
referenced nowhere else in the repo.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

README.md

@@ -11,11 +11,12 @@ Supported target platforms:
 
 ## Current Status
 
-OrbitHub is in active development.
+OrbitHub is in active development, with all planned milestones (M0-M10)
+complete.
 
-- Milestones completed: M0-M9
-- Current milestone: Milestone 10 (v1.0 Stabilization)
 - Latest published release: `v2026.9.28`
+- Versioned by date rather than semantic/`v1.0`-style versioning; see
+  [docs/PROGRESS.md](docs/PROGRESS.md) for the full release history
 - VNC (M6) is fully built out: Raw/CopyRect/Hextile/ZRLE/Tight encodings,
   bidirectional clipboard sync, remote cursor shape sync, and both
   scale-to-fit and actual-size display modes. Standard VNC Authentication