feat: org capacity policy admin surface

ADR-0022 / Spec.System.Capacity pins layered capacity limits: a platform
ceiling per dimension is unbreakable, and each organization may only set a
lower `organizationLimit`. The effective limit is the minimum of the two
(`LayeredLimit.effective`); dimensions with no org override fall back to
the platform ceiling. No dimension may be unlimited (a ceiling must exist
before an org limit can be set, `LayeredLimit.Valid`).

Add the backend: the pinned 23 CapacityDimension set + labels
(src/capacity/dimensions.ts), platform ceilings sourced from existing
runtime env vars plus `HUB_CEILING_<DIMENSION>` (src/capacity/ceilings.ts),
the OrganizationCapacityPolicy prisma model + migration, the
getCapacityPolicy/setCapacityPolicy service enforcing LayeredLimit.Valid,
and org-admin GET/PUT /api/org/:orgSlug/capacity-policy routes wired into
the org route tree.

Add the admin-web surface: CapacityDimension/CapacityPolicyView api client
types, capacityPolicy/setCapacityPolicy methods, a `容量` nav entry, and a
capacity page that lists every dimension with its platform ceiling (or
`未配置` when unset), an org-limit input (disabled until a ceiling exists),
and a live effective-value column. Saving sends the partial limits map;
the service rejects values above the ceiling or for unconfigured dimensions.

hub/admin-web/src/lib/api.ts

@@ -188,6 +188,42 @@ export interface UsageReport {
 	totals: UsageTotals;
 }
 
+export type CapacityDimension =
+	| 'requestRate'
+	| 'requestBodySize'
+	| 'agentConcurrency'
+	| 'admissionQueueLength'
+	| 'admissionQueueWait'
+	| 'fileSize'
+	| 'attachmentCount'
+	| 'archiveExpansion'
+	| 'projectStorage'
+	| 'organizationStorage'
+	| 'memberCount'
+	| 'projectCount'
+	| 'teamCount'
+	| 'folderCount'
+	| 'sessionCount'
+	| 'runWallTime'
+	| 'runTurns'
+	| 'runToolCalls'
+	| 'toolWallTime'
+	| 'runOutputSize'
+	| 'processMemory'
+	| 'processCpu'
+	| 'processCount';
+
+export interface CapacityDimensionRow {
+	dimension: CapacityDimension;
+	platformCeiling: number | null;
+	organizationLimit: number | null;
+	effective: number | null;
+}
+
+export interface CapacityPolicyView {
+	dimensions: CapacityDimensionRow[];
+}
+
 // --- API ---
 
 export const api = {
@@ -297,4 +333,9 @@ export const api = {
 	) => put(`${orgBase(slug)}/feishu-application-connection`, body) as Promise<FeishuApplicationConnection>,
 	disableFeishuApplication: (slug: string) =>
 		del(`${orgBase(slug)}/feishu-application-connection`) as Promise<FeishuApplicationConnection>,
+
+	capacityPolicy: (slug: string) =>
+		get(`${orgBase(slug)}/capacity-policy`) as Promise<CapacityPolicyView>,
+	setCapacityPolicy: (slug: string, body: { limits: Partial<Record<CapacityDimension, number | null>> }) =>
+		put(`${orgBase(slug)}/capacity-policy`, body) as Promise<CapacityPolicyView>,
 };