Add official US and European collection and calendar storage

Collect official RSS and Atom summaries, preserve historical captures, and poll macro releases with bounded cadence and Retry-After handling. Separate news collectors from the economic calendar worker.

Track statistical periods, publication stages, first observations, revisions, and current official series. Include explicit migration files and isolated archive, parsing, and import tests; no migration or import is executed by this commit.

Keep dependency declarations and lockfile together for PDF archives and the upcoming captcha integration. Verify the staged snapshot with 90 focused tests.

backend/tests/fixtures/europe/eurostat_schedule.json

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+[{"recordid": "22494146", "allDay": true, "unit": "F3", "period": "August 2026", "types": [{"label": "Data release", "order": 1}, {"label": "Euro indicators release", "order": 2}, {"label": "Statistics Explained", "order": 4}], "euroind": true, "euroindAuthor": "estat", "start": "2026-10-01T11:00Z", "datasetCodes": "une_rt_m", "theme": "Population and social conditions", "preliminary": false, "title": "Unemployment"}, {"recordid": "22494157", "allDay": true, "unit": "C4", "period": "Q2/2026", "types": [{"label": "Data release", "order": 1}, {"label": "Euro indicators release", "order": 2}, {"label": "News article", "order": 3}, {"label": "Statistics Explained", "order": 4}], "euroind": true, "euroindAuthor": "estat", "start": "2026-10-01T11:00Z", "datasetCodes": "prc_hpi_a,prc_hpi_inw,prc_hpi_q", "theme": "Economy and finance", "preliminary": false, "title": "House price index"}, {"recordid": "22494168", "allDay": true, "unit": "C4", "period": "September 2026", "types": [{"label": "Data release", "order": 1}, {"label": "Euro indicators release", "order": 2}, {"label": "Statistics Explained", "order": 4}], "euroind": true, "euroindAuthor": "estat", "start": "2026-10-02T11:00Z", "datasetCodes": "prc_hicp_fp,prc_hicp_manr,prc_hicp_mmor,prc_hicp_midx,prc_hicp_inw,prc_hicp_cow", "theme": "Economy and finance", "preliminary": false, "title": "Flash estimate inflation euro area"}, {"recordid": "22494179", "allDay": true, "unit": "C2", "period": "Q2/2026", "types": [{"label": "Data release", "order": 1}, {"label": "Euro indicators release", "order": 2}], "euroind": true, "euroindAuthor": "estat", "start": "2026-10-02T11:00Z", "datasetCodes": "nasq_10_nf_tr,nasq_10_ki,nasa_10_nf_tr,naidsq_10_nf_tr,naidsa_10_nf_tr", "theme": "Economy and finance", "preliminary": false, "title": "First release sector accounts (households and businesses)"}, {"recordid": "22494190", "allDay": true, "unit": "C1", "period": "Q2/2026", "types": [{"label": "Data release", "order": 1}, {"label": "Euro indicators release", "order": 2}, {"label": "Statistics Explained", "order": 4}], "euroind": true, "euroindAuthor": "estat", "start": "2026-10-02T11:00Z", "datasetCodes": "bop_c6_q,bop_c6_a,bop_eu6_q,bop_iip6_q", "theme": "Economy and finance", "preliminary": false, "title": "Balance of payments"}, {"recordid": "22494201", "allDay": true, "unit": "G1", "period": "June 2026 - Q2/2026", "types": [{"label": "Data release", "order": 1}], "euroind": true, "euroindAuthor": "estat", "start": "2026-10-02T11:00Z", "datasetCodes": "sts_cobp_m,sts_cobp_q,sts_cobp_a", "theme": "Industry, trade and services", "preliminary": false, "title": "Building permits"}, {"recordid": "22494212", "allDay": true, "unit": "G1", "period": "August 2026", "types": [{"label": "Data release", "order": 1}, {"label": "Euro indicators release", "order": 2}], "euroind": true, "euroindAuthor": "estat", "start": "2026-10-05T11:00Z", "datasetCodes": "sts_inppd_a,sts_inppd_m,sts_inppd_q", "theme": "Industry, trade and services", "preliminary": false, "title": "Industrial producer prices, domestic market"}, {"recordid": "22494223", "allDay": true, "unit": "G1", "period": "August 2026", "types": [{"label": "Data release", "order": 1}], "euroind": true, "euroindAuthor": "estat", "start": "2026-10-06T11:00Z", "datasetCodes": "sts_inpi_m,sts_inpi_q,sts_inpi_a", "theme": "Industry, trade and services", "preliminary": false, "title": "Industrial import prices"}, {"recordid": "22494234", "allDay": true, "unit": "G1", "period": "August 2026", "types": [{"label": "Data release", "order": 1}, {"label": "Euro indicators release", "order": 2}], "euroind": true, "euroindAuthor": "estat", "start": "2026-10-06T11:00Z", "datasetCodes": "sts_trtu_m,sts_trtu_q,sts_trtu_a", "theme": "Industry, trade and services", "preliminary": false, "title": "Retail trade"}, {"recordid": "22494245", "allDay": true, "unit": "G1", "period": "Q2/2026", "types": [{"label": "Data release", "order": 1}], "euroind": true, "euroindAuthor": "estat", "start": "2026-10-06T11:00Z", "datasetCodes": "sts_sepp_q,sts_sepp_a", "theme": "Industry, trade and services", "preliminary": false, "title": "Services producer prices"}, {"recordid": "22494256", "allDay": true, "unit": "G1", "period": "July 2026", "types": [{"label": "Data release", "order": 1}, {"label": "Euro indicators release", "order": 2}], "euroind": true, "euroindAuthor": "estat", "start": "2026-10-07T11:00Z", "datasetCodes": "sts_sepr_m,sts_sepr_q,sts_sepr_a", "theme": "Industry, trade and services", "preliminary": false, "title": "Services production"}, {"recordid": "22494267", "allDay": true, "unit": "C1", "period": "September 2026", "types": [{"label": "Data release", "order": 1}, {"label": "Euro indicators release", "order": 2}], "euroind": true, "euroindAuthor": "ecb", "start": "2026-10-13T11:00Z", "datasetCodes": "", "theme": "", "preliminary": false, "title": "Interest rates (3 months)"}, {"recordid": "22494277", "allDay": true, "unit": "C1", "period": "SeptemberLine truncated