Add conformance schemas, golden fixtures, and UI/layout improvements

.claude/settings.local.json

@@ -100,7 +100,8 @@
       "Bash(echo \"exit: $?\")",
       "Bash(claude plugin *)",
       "Bash(cp \"/root/.claude/uploads/995af0a3-e865-5b96-b002-e90985880970/cc51b77a-spec01codebaseauditandarchitecture.md\" \"/home/user/loki/docs/adr/spec-01-codebase-audit-and-architecture.md\" && echo \"placed\" && ls -la docs/adr/spec-01-codebase-audit-and-architecture.md)",
-      "mcp__code-review-graph__list_graph_stats_tool"
+      "mcp__code-review-graph__list_graph_stats_tool",
+      "mcp__Claude_Code_Remote__send_later"
     ]
   },
   "enableAllProjectMcpServers": true,

.github/workflows/rust.yml

@@ -58,11 +58,18 @@ jobs:
     - name: Install toolchain
       uses: dtolnay/rust-toolchain@stable
     - uses: Swatinem/rust-cache@v2
-    - name: Install xmllint (libxml2)
-      # appthere-conformance's schema axis (Spec 02 M2) shells to xmllint; install
-      # it so those tests actually run instead of skipping. The harness fails
-      # loudly if it is absent, so this keeps the schema axis genuinely exercised.
-      run: sudo apt-get update && sudo apt-get install -y libxml2-utils
+    - name: Install conformance tools (xmllint, pdftoppm)
+      # Spec 02 gates, all running as ordinary cargo tests in this job:
+      # - schema axis (M2): loki-{ooxml,odf} schema_validation.rs shell to
+      #   xmllint against the vendored ISO 29500 / ODF schemas — HARD gate.
+      # - round-trip axis (M3): conformance_round_trip.rs suites — HARD gate.
+      # - visual axis (M5): loki-render-cpu visual_golden.rs compares
+      #   vello_cpu renders to the committed LO goldens at the calibrated
+      #   tolerance; needs pdftoppm only for the raster wrapper's own tests.
+      #   Advisory-by-construction: the known kerning divergence is pinned as
+      #   an expected-failure canary (see goldens/CALIBRATION.md).
+      # Each harness fails loudly if its tool is absent — never skips.
+      run: sudo apt-get update && sudo apt-get install -y libxml2-utils poppler-utils
     # `--all-features` so the feature-gated format crates (pptx, xlsx) and their
     # integration tests actually compile and run — under the default feature set
     # `cargo test --workspace` silently skips `#![cfg(feature = ...)]` suites.

CLAUDE.md

@@ -199,8 +199,8 @@ but are **not perfectly round-tripped through the Loro CRDT**.
 
 | Field(s) | Status | Priority |
 |---|---|---|
-| `tab_stops` | Written as unreadable Debug string; not read back. | Medium |
-| `background_color` (paragraph) | Written as Debug string; not decoded on read. | Low |
+| `tab_stops` | **DONE** (2026-07-04) — structured `"pos:Align:Leader;…"` codec (`loro_bridge/decode.rs`) written and read back; tested by `bridge_tab_stops_roundtrip`. Pre-fix Debug strings decode as absent. | — |
+| `background_color` (paragraph) | **DONE** (2026-07-04) — total `DocumentColor` codec (`loro_bridge/color_codec.rs`, covers Rgb/Cmyk/Theme/Transparent) written and read back; tested by `bridge_para_background_color_roundtrip`. | — |
 | `DocumentMeta` / `DublinCoreMeta` | Round-trips **through the Loro CRDT** (`loro_bridge::meta`) **and is written back on export** — core properties + extended Dublin Core reach DOCX (`docProps/core.xml` + `custom.xml`) and ODT (`meta.xml`), tested by `metadata_round_trip.rs` / `extended_dublin_core_round_trips`. Remaining tail (not the Loro bridge): custom user properties, `meta:editing-duration`, and OOXML `docProps/app.xml` are still not written. | Low |
 
 ---