chore: reconcile on-client path + add golangci-lint config (R13+R14)

R13 — on-client path reconciliation:
- AGENTS.md: 6 occurrences of /opt/homelab-context/ → /opt/homelab/
  (sections 1, 2, 5, 7)
- .agents/NOMOS.md: 2 occurrences of /opt/homelab-context/ → /opt/homelab/
- CLIENTS.md already used /opt/homelab/ — now consistent across all docs.
  The repo is still named 'homelab-context' (git remote), it just clones
  to /opt/homelab/ on enrolled clients per CLIENTS.md.

R14 — golangci-lint/staticcheck/govulncheck tooling:
- .golangci.yml (new): config enabling govet, staticcheck, ineffassign,
  unused, errcheck, gosimple, typecheck, misspell, revive. Excludes
  generated code (internal/httpapi/gen/, internal/db/sqlcgen/) and
  relaxes errcheck in test files.
- Makefile: split 'lint' target into vet, golangci, govulncheck subtargets.
  Each checks if the tool is installed and prints install instructions
  if not. 'make lint' runs all three.
- CI already had golangci-lint-action + govulncheck (both advisory);
  the action auto-discovers .golangci.yml.

plans/2026-07-17-codebase-review-and-cleanup.md

@@ -434,8 +434,8 @@ the gitignore comment); `build` target ensures `bin/` exists; `clean` removes `b
 | R10 | Replace `<svelte:component>` in `ActivityTimeline.svelte:103`; fix `state_referenced_locally` warnings | S | Low | ✅ done |
 | R11 | Add the 8 manually-registered `serve*` routes to `openapi.yaml` (or document the carve-out) | S | Low | ✅ done — documented the carve-out |
 | R12 | Add `docs/mbse/README.md` "Last verified" header + scheduled re-verification; normalize ADR 0013/0014 template | S | Low |
-| R13 | Reconcile on-client path (`/opt/homelab/` vs `/opt/homelab-context/`) across AGENTS.md + CLIENTS.md | S | Low |
-| R14 | Install `golangci-lint`/`staticcheck`/`govulncheck` locally + in CI | S | Low |
+| R13 | Reconcile on-client path (`/opt/homelab/` vs `/opt/homelab-context/`) across AGENTS.md + CLIENTS.md | S | Low | ✅ done |
+| R14 | Install `golangci-lint`/`staticcheck`/`govulncheck` locally + in CI | S | Low | ✅ done — `.golangci.yml` config + split Makefile targets |
 
 ## G. Verification