feat: Go walking skeleton for cmd/ingestion

[koinsaari]

What

Replaces the placeholder cmd/ingestion with a working Go binary that reads a .osm.pbf file, filters to POIs, transforms them into models.Place records, and bulk-upserts them into the places table.

Changes

• Add internal/osm package: PBF streaming via paulmach/osm, allowlist-based POI filter, node-to-place transformer, rank derivation
• Add internal/place repository with UpsertBatch using (osm_id, osm_type) conflict key
• Add migration 000007 with partial unique index on (osm_id, osm_type) WHERE osm_id <> 0
• Expand models.Category to cover the OSM POI taxonomy (Bar, Healthcare, Education, Finance, Entertainment, Government, Transport, Social, Worship)
• Replace the cmd/ingestion placeholder with a full-import dispatcher; diff-sync is wired up to print "not implemented" for now
• Add end-to-end integration test against a small Andorra fixture PBF
• Add testhelpers.StartPostgresWithConnInfo so cmd/ingestion tests can build their own configs from a testcontainers PostGIS instance
• Update CLAUDE.md to describe the new internal/osm and internal/place packages and the real cmd/ingestion role

Notes

• First slice of the larger Kotlin → Go migration captured in docs/superpowers/migration-roadmap.md. Accessibility ingestion, diff-sync, and place soft-vs-hard-delete logic come in later sub-projects.
• The migration's partial predicate (WHERE osm_id <> 0) lets existing cmd/api tests keep creating places without OSM IDs. In production every place is OSM-sourced and has a non-zero osm_id, so the predicate covers every real row. A follow-up issue should settle whether POST /places (the endpoint that justifies the partial predicate) should be removed.
• Andorra fixture is 3.2 MB committed to testdata/; gives the smoke test ~492k nodes to process and ~976 places to import.

Test plan

• go test ./... — all unit tests pass
• go test -tags integration -timeout 300s ./... — all integration tests pass (including the pre-existing cmd/api ones that rely on the partial-index predicate)
• go vet ./... clean

[claude]

Claude finished @koinsaari's task in 3m 12s —— View job

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Review

• Read CLAUDE.md
• Read changed files
• Analyze for must-fix issues
• Post review

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No must-fix issues found. The PR is clean and ready to merge.

A few observations for completeness:

internal/osm/filter.go — building branch

buildingQualifyingKeys includes "amenity" and "public_transport". A node with building=yes + amenity=<unknown> (e.g. amenity=bench) would slip through as CategoryOther instead of being filtered out, because the amenity branch only catches values in amenityToCategory. In practice this is harmless — building=yes almost never appears on OSM nodes (buildings are mapped as ways/relations), so this code path is essentially unreachable in real data. Worth knowing about if the pipeline is ever extended to process ways.

internal/place/repository.go — source not in DoUpdates

source is intentionally omitted from the conflict-update columns. Since every row from this pipeline has source="osm", this is correct. Just noting it so a future reader doesn't add it by mistake.

cmd/ingestion/main_integration_test.go — double migration

StartPostgresWithConnInfo runs migrations, and then runFullImport runs them again on the same container. golang-migrate handles this gracefully (ErrNoChange), so no issue.

[claude]

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Tasks

• Read CLAUDE.md
• Read changed files
• Analyze for must-fix issues
• Post review