v0.9.0

Minor: receipt dollars are now explicit observable lower bounds — ≥ $X, never an
exact-looking bill — and the --json export schema moves to v2 to say so in a
machine-readable way. A second, deeper cost-correctness pass after v0.7.1's #196:
PR #242 fixed real undercounting (a commit/amend truncation had sliced a $0.44
receipt out of work independently reconstructed at ≥ $44.97, issue #239) and made
every surface state what the number is and what it excludes.

feat

• GPT-5.6 (Sol/Terra/Luna) sessions are now priced. The price schema gained
  per-request context tiers (context_tiers, input_cache_write), so Codex request
  envelopes select the cited >272K Standard tier per request; the unpersisted
  cache-write quantity stays outside the floor with a caveat. GPT-5.5 remains
  tokens-only because its published long-context threshold is full-session scoped,
  which a request stream cannot select honestly (PR #242, cited from the official
  model pages in data/prices/openai.json).
• Statusline model segment + the meter (SPEC-0076, PR #233): the statusline can
  show the session's model mix, and the landing page gained the meter story and
  redesign.
• PR-receipt provenance footer (SPEC-0078, PR #236): posted receipts carry a
  footer stating how the numbers were produced and where the raw data lives.
• Samosa story page (SPEC-0079, PRs #238/#240): a Ko-fi tip jar behind an
  own-surfaces-only story page; a single Sponsor row and README section link to it.
  Receipts, PR comments, and artifacts never carry the tip link by default.
• Landing SEO/AEO (SPEC-0080, PR #243): share cards, JSON-LD, sitemap, llms.txt.
• Exports: schema v2 adds minUsd lower-bound estimates (kind: "lower-bound",
  basis: "standard-api-list-price-equivalent"), exact parent/child/combined
  unpriced-token vectors, explicit dollar/token scopes, combined pricing-coverage
  fields, and tool-CSV granularity warnings (PR #242).

fix

• Cost attribution across all agents (PR #242, fixes #239): PR anchors resolve
  one recovered SHA-alias truth for contributor selection, slicing, per-commit rows,
  and same-session amend lineage (with HEAD-change barriers so a branch switch can
  never pull a foreign commit into a slice). Codex parsing gains replay dedupe,
  inherited-baseline removal, model/provider switching, exact cumulative/last
  reconciliation, and fail-closed handling of malformed/reset/mixed streams — every
  observable envelope is retained as tokens even when pricing must be refused.
  Claude Code deduplicates by message.id and keeps id-less usage as one
  unattributed envelope; malformed counters can never become priceable zeroes.
  OpenCode prices provider-aware and reconciles aggregates componentwise —
  contradictory vectors are excluded, never fabricated.
• Uncited cache rates contribute zero with a caveat — no fallback to an uncited
  input rate, ever (I2).
• Displayed ledger rows sum exactly to TOTAL, and no displayed amount ever exceeds
  its raw value; tiny positive floors keep up to twelve decimals rather than
  collapsing to $0.0000 (PR #242).
• Detector language: flagged patterns read FLAGGED PATTERN COST ≈ … · not proven savings — no "waste floor" claim (PR #242).
• PR receipt attachment is reliable across Codex and CI (PR #232).

BREAKING / migration from schemaVersion 1

--json schemaVersion is now 2. totalUsd is scoped to the parent session
only and is an explicit lower bound (rounded down); the old combined meaning lives
in combinedPricedUsd / combinedPricedCostEstimate. Scripts that consumed v1's
totalUsd should check schemaVersion and read the combined fields if they want
parent+subagent totals. All dollar fields carry lower-bound semantics objects; known
unpriced usage is exported beside the floor instead of disappearing. Details in
docs/json-schema.md.