docs: Finch, the author's language, for SchOS's own programs

A plan, deferred behind the 1.0 freeze like everything else here: what
Finch is today (measured from its repository: LLVM, self-hosting boot/
compiler, C import, targets), what SchOS would need, and the open
question of what "finishing" it means.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015f73FesGZGYPkmDvUcj6QX

docs/plan/README.md

@@ -48,6 +48,12 @@ And the one the hybrid mechanisms were built for:
 | ~~ldls.md~~ | **Built.** The Linux Driver Layer for SchOS: someone else's drivers, in a process, reached through `/dev/pci`. `ping` works over `8139too` and over `e1000`. The description moved to [../architecture/ldls.md](../architecture/ldls.md). |
 | ~~debugger.md~~ | **Built**, all of it, including the network transport. A debugger that observes rather than halts and answers in this kernel's own vocabulary: symbols, a log that outlives the kernel, `/dev/dbg`, `whose`, hardware watchpoints, and `schdbgd`. The description moved to [../architecture/debugging.md](../architecture/debugging.md). |
 
+And one for after 1.0, recorded so the decision is not lost:
+
+| | |
+|---|---|
+| **[finch.md](finch.md)** | **Later.** The author's own LLVM language, Finch, for SchOS's applications and tools in place of C. Already self-hosting; the plan is a target, bindings generated from `include/uapi/`, and the compiler in the image. |
+
 Two longer-horizon documents sit behind these: [schapi.md](schapi.md), the API
 layering and the compatibility promise, and [roadmap.md](roadmap.md), which holds
 everything still open that is not one of the three above.