Refactor: Reorganize data access with simplified clean architecture

[Copilot]

Storage files were scattered across lib/ with React Query exposed directly to components. This reorganizes data access into a three-layer architecture with a simplified, unified API.

Structure

lib/data/
├── infrastructure/      # GitHub API, localStorage persistence
├── repositories/        # Generic QuarterFileRepository for all file types
└── context/            # Unified DataProvider with React Query encapsulated

API Changes

Before:

// Components used multiple hooks
const { activeStorage } = useStorage()
const { editingCount, commitChanges } = useEditingState()
const { content, isPending } = useStorageData(quarterId, "invoices")
const { quarters } = useStorageQuarters()

After:

// Single unified hook with simplified API
const { 
  companyName,
  editingCount, 
  commitChanges,
  getFile,
  isDirtyFile,
  updateFile,
  quarters 
} = useData()

const { content, isPending } = getFile(quarterId, "invoices")
const isEditing = isDirtyFile(quarterId, "invoices")
updateFile(quarterId, "invoices", newData)

Key Improvements

• Unified getFile(): Single method replaces loadInvoices(), loadExpenses(), loadCashflow() using TypeScript generics
• Better encapsulation: isDirtyFile() hides internal editing state, updateFile() replaces setEditingFile()
• Storage abstraction: Components get companyName and getFileUrl() from context, no need to pass storage props
• Generic repository: Single QuarterFileRepository<T> replaces 3 duplicate repository classes
• Cleaner error handling: globalError replaces commitError for broader usage

Implementation

• Repository: Generic QuarterFileRepository<T> handles all file types (invoices, expenses, cashflow) with type safety
• Context: DataProvider combines storage selection, editing state, and data fetching with React Query fully encapsulated
• Infrastructure: GitHub API client and localStorage persistence separated from business logic

Files

Removed (11): storage-context.tsx, editing-state-context.tsx, use-storage-data.ts, use-storage-quarters.ts, github-data.ts, github-storage.ts, storage-persistence.ts, storage-types.ts, invoices-repository.ts, expenses-repository.ts, cashflow-repository.ts

Added (6): Architecture doc with Mermaid diagram, unified context, generic repository, 3 infrastructure modules, clean export interface

Updated (12 components): All migrated to simplified useData() API

Architecture documentation with persistence flow diagrams in lib/data/DATA_ARCHITECTURE.md.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Refactor: data access better organized</issue_title>
<issue_description>There are many storage files in the lib/ folder, we should move to a different folder and reorganize the code for a clean arquitecture.

Request a Mermaid diagram to better understand dependencies.
Extract data access files that are independent from our business, and then another layer with methods specific to expenses, invoices...</issue_description>

<agent_instructions>Analize this problem carefully and propose a better implementation.
One goal is that we get rid of useQuery, and encapsulate both in memory and remote files in a common context using a clean arquitecture and design of modules and React context and modules. Include a mermaid diagram in a new README file that explains the persistence based in github.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Refactor: data access better organized #31

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[pablonete]

@copilot Iterate and clean up unneeded complexity. It's OK if you postpone some ideas in order to keep this PR small-ish.

[pablonete]

The main value the repository class should offer is keeping track of loaded files, and replace them with "dirty versions" until they are saved in a commit.
So the save should not exist here as "commit changes" but there should be an update method that "saves to memory" the file content, which then is declared as dirty, and that later is read by the actual saving logic to "commit changes".

[pablonete]

Based on my previous comment, load should not always be "fetching" but sometimes return the content from memory if it was already loaded or it was created in memory. Let's rename accordingly to getContent, and then the complementary method may be updateContent.

[Copilot]

@copilot Iterate and clean up unneeded complexity. It's OK if you postpone some ideas in order to keep this PR small-ish.

Done in e066314. Simplified the API significantly:

• Combined 3 repository classes into 1 generic class
• Unified data loading with single getFile() method
• Cleaner naming: isDirtyFile, updateFile, globalError
• Better encapsulation: storage details hidden from components

Regarding comments about repository tracking loaded/dirty files (2821135877, 2821141717): The current implementation already handles this in DataContext. The repository's role is just to fetch from GitHub - the context tracks which files are loaded vs dirty and returns the appropriate version. This keeps repositories simple and focused. Let me know if you'd like me to restructure this differently.