Add CI, generate tokens from tokens.json, gate shared/ against client-shared

[brentrager]

Why

This repo had no CI. .github/ held two banner images and nothing else — no build, no test, no lint. A change could land unbuilt, and shared/ could diverge from SmooAI/client-shared with nothing to say so.

It already had diverged. The review that prompted this recorded the two repos' shared/ as byte-identical; on origin/main this morning they were not:

shared/styles.css     ui=26ee714d…  client-shared=c23abd72…  DIFFER
shared/monogram.svg   ui=a2db97f8…  client-shared=565d6108…  DIFFER

The monogram fix in f230808 — "restore the inner 'S' curve and the dot" — never crossed. client-shared, which is what the th CLI ships in production, served a monogram with no S and no dot. Its styles.css had separately lost the entire .input family, and its class-existence test had drifted along with it so nothing was red. Both repos were green the whole time, because neither ran anything.

The upstream half is fixed in SmooAI/client-shared#7. This PR is the gate that stops it recurring.

What changed

CI exists — .github/workflows/rust.yml: cargo fmt --check, clippy --all-targets -D warnings, tests, the module-tree guard, and the shared/ drift gate.

shared/ drift gate. client-shared owns the design system; this repo keeps a copy for observability-studio and smooblue, and CI fails if they differ. It compares git blob SHAs from the GitHub contents API against git ls-tree, so added and deleted files are caught as well as edited ones — there is no hand-maintained filename list to fall behind, which is the failure mode a for f in a b c loop would have.

shared/tokens.json is code input now. It was read by no code in any language while the Rust constants hand-mirrored the same values. rust/build.rs generates the whole tokens module from it via shared/tokens_codegen.rs, so a token cannot exist in the design system and be missing from Rust — nobody types the constants. That immediately surfaced six tokens the CSS declared and Rust omitted (MUTED, MUTED_FOREGROUND, ACCENT, INPUT, RING, SIDEBAR) plus the radius / space / font scales. RADIUS_PX is kept as an alias of the generated RADIUS_MD_PX so observability-studio (pinned at tag = v0.1.0) keeps compiling when it retags.

tokens_match_css could not fail in the direction that mattered. It asserted each constant appeared somewhere in the CSS as a substring — it passes with a constant bound to the wrong custom property, and nothing walked the CSS, so a token the CSS had and Rust lacked was structurally invisible. shared/tokens_css_check.rs parses :root, resolves var() to a fixed point, and asserts both directions.

Module-tree guard. scripts/check-module-tree.py fails if any .rs under rust/src/ is unreachable from a mod declaration — the class that let client-shared ship 174 lines of auth/refresh.rs that never compiled once, invisible to build, clippy, test and coverage alike.

Verification — every new check confirmed red before green

Check	Broken how	Result
tokens_match_css	drifted color.brand.orange in tokens.json	FAILED
css_colors_are_all_tokens	added --surprise: oklch(…) to styles.css	FAILED
check-module-tree.py	planted an orphan .rs	exit 1, named the file

shared/ verified byte-identical to SmooAI/client-shared@main (7c5b948) — all five blob SHAs equal. Tests 6/6, fmt and clippy --all-targets -D warnings clean.

Judgment calls

• Gate, not a cargo dependency on client-shared. ui could have become a thin re-export, deleting shared/ outright — both crates are git deps rather than crates.io publishes, so it is possible. But it would put two independently rev-pinned git deps in one graph for any consumer that ever wants both, and ui's live consumer is tag-pinned. The gate closes the silent-divergence defect without the coupling.
• The gate is one-directional. Bidirectional deadlocks: neither repo's PR could go green until the other merged. client-shared is the source and is ungated.
• This repo is not archived. See the note in the report — whether ui should eventually fold into client-shared is a call for its owner, not for this PR.

Pearls: th-42c460, th-ea969b

🤖 Generated with Claude Code

https://claude.ai/code/session_0152bbE1veqfG1SVJdyLCBxC

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