feat(cache-valkey): initial implementation — Provider, adapters (v1.0.0)

Introduces code.nochebuena.dev/einherjar/cache-valkey — the Valkey cache starter
for the Einherjar framework. Absorbs the valkey package from micro-lib and adds
three duck-typed adapters that wire directly into auth, web, and auth-jwt.

Core:
- Provider interface — Get, Set, Del, Exists, Expire, IncrWithTTL, Native()
- Component interface — lifecycle.Component + observability.Checkable + Provider
- Config struct (EINHERJAR_VALKEY_* env vars)
- New(logger, cfg) Component — creates valkey-go client in OnInit;
  PING in OnStart; logs "valkey: connected"
- IncrWithTTL implemented with Lua script (atomic INCR + conditional EXPIRE);
  race-free fixed-window semantics with no MULTI/EXEC overhead
- Priority: LevelDegraded — Valkey outage degrades, does not halt the service

Adapters (duck-typed — no import of auth, web, or auth-jwt):
- PermissionCache — Get/Set int64 bitmasks as string; satisfies auth/rbac.Cache
- RateLimiterStore — fixed-window via IncrWithTTL; satisfies web/mw.RateLimiterStore
- Blacklist — Exists/Set "1" with TTL; satisfies auth-jwt.Blacklist

Compliance test verifies CT-6, duck-type shape assignments, and full adapter
behavioural coverage with a mockProvider (no live server required).

- Component interface embeds observability.Identifiable; identifiable.go implements
  ModulePath and ModuleVersion via runtime/debug.ReadBuildInfo() — prints in launcher banner

blacklist.go

@@ -0,0 +1,41 @@
+package cachevalkey
+
+import (
+	"context"
+	"time"
+)
+
+// blacklistShape mirrors auth-jwt.Blacklist for compile-time duck-type verification.
+// Cache-valkey must not import auth-jwt (D-1), so the shape is defined locally.
+type blacklistShape interface {
+	IsRevoked(ctx context.Context, jti string) (bool, error)
+	Revoke(ctx context.Context, jti string, ttl time.Duration) error
+}
+
+var _ blacklistShape = (*Blacklist)(nil)
+
+// Blacklist is a Valkey-backed JWT refresh token revocation list.
+// Satisfies auth-jwt.Blacklist via duck typing — no import of that package required.
+//
+// JTIs are stored as keys with their remaining TTL; the entry expires naturally
+// when the token would have expired. Keys are stored as-is (JTIs are UUIDs and
+// do not collide with permission cache keys).
+type Blacklist struct {
+	provider Provider
+}
+
+// NewBlacklist returns a Blacklist backed by p.
+func NewBlacklist(p Provider) *Blacklist {
+	return &Blacklist{provider: p}
+}
+
+// IsRevoked reports whether the refresh token identified by jti has been revoked.
+func (b *Blacklist) IsRevoked(ctx context.Context, jti string) (bool, error) {
+	return b.provider.Exists(ctx, jti)
+}
+
+// Revoke marks jti as revoked for the given TTL.
+// TTL should match the token's remaining lifetime so the entry expires naturally.
+func (b *Blacklist) Revoke(ctx context.Context, jti string, ttl time.Duration) error {
+	return b.provider.Set(ctx, jti, "1", ttl)
+}