Sync to the current Tango API: budget, DIBBS, exclusions, SBIR, detail GETs, filter parity (v0.2.0)

[makegov-mark]

Summary

Brings the Rust SDK up to the current public Tango API and prepares 0.2.0 (workspace version already bumped; cargo publish --dry-run passes for both crates).
Rebased onto main, so it now sits on top of SLED, contract appeals and the protest-casing fixes.
Every route and filter below was checked against the live OpenAPI schema and the API source, not against another SDK.

Breaking

• Removed get_idv_summary and list_idv_summary_awards. Their paths (/api/idvs/{key}/summary/ and /summary/awards/) have never existed, so every call returned 404. Use get_idv with SHAPE_IDVS_COMPREHENSIVE and list_idv_awards.
• Removed search_opportunity_attachments and SearchOpportunityAttachmentsOptions. The API retired /api/opportunities/attachment-search/, which now returns 404 for every query. list_opportunities with search covers attachment text.

Added

• Budget accounts: list_budget_accounts / iterate_budget_accounts, get_budget_account, get_budget_account_quarters (with tas), get_budget_account_recipients (with funding_organization_id), and get_entity_budget_flows (with fiscal_year). SHAPE_BUDGET_ACCOUNTS_MINIMAL mirrors the API's default shape.
• DIBBS (RFQs, RFPs, awards), SAM exclusions, and SBIR/STTR topics and solicitations: list / get / iterate for each, options builders that name every filter the API accepts, and suggested shapes.
• Singleton detail GETs: get_contract, get_opportunity, get_notice, get_forecast, get_grant, get_subaward; contract sub-routes list_contract_subawards and list_contract_transactions.
• Filters the API accepts that the SDK did not name: key on contracts / IDVs / OTAs / OTIDVs, grant_id, cage (an alias of cage_code), notice_id / department / office on notices, opportunity_id, forecast id, previous_uii, SLED verbose, and the budget identity filters.

Fixed

• Docs: cage is an alias, not a distinct filter; department code is an integer; the child-IDV route is /api/idvs/{key}/idvs/.
• Department code: the Go SDK decodes department code as a string while the API returns an integer. This SDK is not affected (department records and the nested department on AgencyRecord are untyped JSON); wire tests now pin both shapes.
• CI: the 1.80 test jobs were running stable, because rust-toolchain.toml overrides the toolchain the action installs. The job now sets RUSTUP_TOOLCHAIN, the lockfile is re-resolved for the 1.80 floor, and .cargo/config.toml keeps later cargo update runs MSRV-aware.

Not in this PR

• G2X (/api/events/, /api/news/, /api/company/rag/), the canonical /api/webhooks/subscriptions/ CRUD, and account-usage endpoints, matching what the other SDKs cover.
• Typed filter fields on the award sub-resource lists (entity / agency / IDV / vehicle sub-routes). Those filters are reachable today through each options builder's extra map.

Test plan

• cargo fmt --all --check
• cargo clippy --workspace --all-features --all-targets -- -D warnings
• cargo test --workspace --all-features on stable and on 1.80 (315 tests, including a new httpmock wire suite for every added route)
• RUSTDOCFLAGS="-D warnings" cargo doc --no-deps --workspace
• cargo publish --dry-run for makegov-tango and makegov-tango-webhooks

🤖 Generated with Claude Code

~ Mark