feat: overhaul all 12 sector extensions with full CRUD, validation, and tests

Add shared components (ConfirmDeleteDialog, EditEntryDialog, validation utils),
enhance all 12 extension workspaces with edit/delete dialogs, input validation,
period comparisons, and new analytics features. Fix critical bugs in
ProjectBilling margin calculation and EarningsPerLiter revenue allocation.
Add pure calculation modules with 183 new tests across all extensions.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/extensions/use-extension-data.ts

@@ -0,0 +1,86 @@
+'use client'
+
+import { useState, useEffect, useCallback, useRef } from 'react'
+
+interface ExtensionDataRecord {
+  id: string
+  key: string
+  value: Record<string, unknown>
+  created_at: string
+  updated_at: string
+}
+
+export function useExtensionData(sector: string, slug: string) {
+  const [data, setData] = useState<ExtensionDataRecord[]>([])
+  const [isLoading, setIsLoading] = useState(true)
+  const basePath = `/api/extensions/${sector}/${slug}/data`
+  const mountedRef = useRef(true)
+
+  useEffect(() => {
+    mountedRef.current = true
+    return () => { mountedRef.current = false }
+  }, [])
+
+  const refresh = useCallback(async () => {
+    setIsLoading(true)
+    try {
+      const res = await fetch(basePath)
+      if (res.ok) {
+        const json = await res.json()
+        if (mountedRef.current) setData(json.data ?? [])
+      }
+    } finally {
+      if (mountedRef.current) setIsLoading(false)
+    }
+  }, [basePath])
+
+  useEffect(() => {
+    refresh()
+  }, [refresh])
+
+  const save = useCallback(async (key: string, value: Record<string, unknown>) => {
+    const res = await fetch(basePath, {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ key, value }),
+    })
+    if (res.ok) {
+      const json = await res.json()
+      setData(prev => {
+        const idx = prev.findIndex(d => d.key === key)
+        if (idx >= 0) {
+          const updated = [...prev]
+          updated[idx] = json.data
+          return updated
+        }
+        return [...prev, json.data]
+      })
+      return json.data
+    }
+    return null
+  }, [basePath])
+
+  const remove = useCallback(async (key: string) => {
+    const res = await fetch(`${basePath}?key=${encodeURIComponent(key)}`, {
+      method: 'DELETE',
+    })
+    if (res.ok) {
+      setData(prev => prev.filter(d => d.key !== key))
+    }
+  }, [basePath])
+
+  const getByPrefix = useCallback(async (prefix: string): Promise<ExtensionDataRecord[]> => {
+    const res = await fetch(`${basePath}?prefix=${encodeURIComponent(prefix)}`)
+    if (res.ok) {
+      const json = await res.json()
+      return json.data ?? []
+    }
+    return []
+  }, [basePath])
+
+  const getByKey = useCallback((key: string) => {
+    return data.find(d => d.key === key) ?? null
+  }, [data])
+
+  return { data, isLoading, save, remove, getByPrefix, getByKey, refresh }
+}