chore: expand mise.toml with remaining dev tools, add lefthook, clean up CI

[brucearctor]

Goal

Make the repo fully self-contained for local development via mise install — clone, install tools, build. No hunting for binaries.

PRs

PR	Scope	Risk	Status
#1386	Add tools to mise.toml + remove redundant CI installs	Low	Open
#1387	Extract composite action + selective mise installs	Medium (depends on #1386)	Open
#1388	Lefthook, mise-bump workflow, README update	Zero (independent)	Open

Supersedes

• chore: expand mise.toml with dev tools, add lefthook, clean up CI #1384 (closed — split into the 3 PRs above)

Context

mise.toml was introduced in #1382 for protoc. This effort expands it to cover all external dev tools:

• temporal CLI (replaces temporalio/setup-temporal action)
• cargo-component (replaces cargo install --locked cargo-component)
• cargo-msrv (replaces cargo install cargo-msrv)

Additionally:

• Extracts a composite action to DRY up the 4-step CI setup pattern across 10 jobs
• Adds selective mise install per job (only install what each job needs)
• Adds opt-in git hooks via lefthook
• Adds weekly automated version bump workflow for mise-managed tools

[brucearctor]

While I prefer nix, the stated intention was for mise.

This issue and PR should make that story a bit more complete.

@chris-olszewski , @Sushisource

Also -- i assume the intent is for then mise to be used across all the SDK repos/languages? So, we probably need tickets in each?