refactor: the vocabulary of a collected fact is a package (ADR 0065)

[kfeofantov]

internal/collector was three packages under one name: the vocabulary of
collected facts, the Kubernetes adapter that fills it in (informers, listers,
the kubelet poller), and the reductions that shrink an object to what ships.
Only the middle one needs a cluster — but journal, metadata, revisions,
inventory and sink all imported collector to name a type, and so linked
client-go to do window arithmetic.

47 plain-data types move to internal/model. It imports nothing beyond time
and reflect, and a test in the package asserts that: it is the whole point,
and nothing else in the build would fail if it stopped being true. collector
keeps the watchers, the poller, the filter and every reduction, and is now
imported only by cmd/agent.

Reasoning, alternatives (aliases, splitting collector by concern first) and
what was given up are in ADR 0065.

Result

package	before	after
journal, metadata, revisions	458 packages, 261 client-go	2, none
sink	486, 261	37, none
inventory / pprofprobe / targeting	via collector	4 / 5 / 2, none
collector	458, 261	458, 261 — it is the adapter

collector: 5801 → 4946 lines, 95 → 48 exported declarations.

Why this is reviewable

It is a move, and that is checkable rather than asserted:

• The golden payload bytes are byte-identical — git status internal/sink/testdata is clean.

• Normalizing both trees (drop the moved blocks, drop the model. qualification
  and the import line, collapse whitespace) leaves four changed lines in the
  whole repository:

  internal/collector/nodes.go        prev.sameAs(info)   -> prev.SameAs(info)
  internal/collector/nodes_test.go   info.sameAs(want)   -> info.SameAs(want)
  internal/collector/policy.go       (r ResourceAmounts) empty() -> amountsEmpty(r)
  internal/collector/policy_test.go  one gofmt line-wrap, from a longer signature
  

Both renames are the same seam the package split follows, and both are stated in
the ADR.

Checks

$ go test -race ./...        # green, golden tests included
$ go vet -tags e2e ./...     # clean
$ golangci-lint run ./...    # 0 issues
$ make vulncheck chart-lint  # clean

e2e is running locally against kind; result to follow. No docs/security.md
change: nothing collected, stored or transmitted is different.

🤖 Generated with Claude Code

https://claude.ai/code/session_011YRKuL97KRndaopfpixrhp