chore(provider): rename stuttering ProviderConfig -> Config (isolated, quiet-tree) #39

Summary

Rename the stuttering type provider.ProviderConfig -> provider.Config (and constructor param names accordingly). Pure mechanical stutter-fix, no behavior change.

Context

This was extracted from a larger, stale "pointer-refactor" idea (pass structs by pointer + rename + collapse dual value/pointer handling of DatabaseDetails/CacheDetails) found in an abandoned worktree during a July 2026 cleanup pass. The other two parts were deliberately declined:

• Pointer-passing introduces nil-ability + aliasing (new nil-guard burden) for no hot-path win.
• Collapsing the dual value/pointer DatabaseDetails/CacheDetails handling to pointer-only is correctness-risky: the dual-handling on main (cmd/*.go, scheduler.go, coverage.go) is defensive because different producers emit value vs pointer forms; collapsing it risks a silent type-assertion miss unless every producer is audited first. Not worth it.

Only the rename is a clean, low-risk win, and only worth doing in isolation.

Why isolate + defer

ProviderConfig is used across the whole provider-construction path + tests, so the rename cascades widely and is a merge-conflict magnet. Do it as its own tiny PR only when no other PRs touch provider construction (a quiet-tree window), to avoid churning in-flight work.

Scope (keep it mechanical)

• Rename the type ProviderConfig -> Config in the provider package and update all references/tests.
• Do NOT change any signatures to pointers, and do NOT touch the DatabaseDetails/CacheDetails dual-handling.
• Verify: go build ./... + go test ./... green, golangci-lint clean, .golangci.yml unchanged.

Acceptance

• provider.ProviderConfig no longer exists; provider.Config used everywhere; all tests pass; zero behavior change.