claude-opus-5 / claude-sonnet-5 price at $0, and the documented models.dev.json override is never loaded

[willwashburn]

Two composing defects leave the ledger blind on two of the three Anthropic models in daily use. Observed on burn 4.0.0 (burn summary --since 7d: claude-opus-5 … $0.00, claude-sonnet-5 … $0.00, with the no pricing for model(s) warning, while claude-fable-5 prices correctly).

1. Vendored snapshot is missing the models. crates/relayburn-sdk/data/models.dev.json → anthropic.models contains claude-fable-5 and the 4.x line, but not claude-opus-5 or claude-sonnet-5. Current first-party rates (per MTok):

model	input	output	cache_read (0.1×)	cache_write (1.25×, 5m TTL)
claude-opus-5	$5	$25	$0.50	$6.25
claude-sonnet-5	$3	$15	$0.30	$3.75

(Sonnet 5 has intro pricing of $2/$10 through 2026-08-31; the table above is the sticker rate.) pnpm run pricing:update should pick both up from models.dev.

2. The user override file is documented but never read. The README ("User overrides live at $RELAYBURN_HOME/models.dev.json") and the summary command's own warning hint ("add an override at $RELAYBURN_HOME/models.dev.json", crates/relayburn-cli/src/commands/summary/human.rs:597) both point at the override path — but every non-test call site passes load_pricing(None):

• query_verbs/summary/mod.rs (3 sites)
• query_verbs/sessions.rs:51,200
• query_verbs/compare.rs:129

load_pricing(Some(path)) and the shallow-merge logic exist and are unit-tested (pricing.rs), but no runtime path resolves $RELAYBURN_HOME/models.dev.json and passes it in. Verified empirically: writing a correct override there, then burn state rebuild index && burn ingest, still reports $0 with the no-pricing warning.

Fix shape: resolve <ledger_home>/models.dev.json wherever the ledger home is already resolved and thread it into load_pricing at the query-verb call sites, plus refresh the vendored snapshot. Either half alone unblocks; both are correct.

Why it matters: budget enforcement built on burn summary --session silently under-reports any opus-5/sonnet-5 seat as free — the exact models most worth metering.