docs(phase-2): capture phase context

.planning/phases/02-data-persistence-file-management/02-CONTEXT.md

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+# Phase 2: Data Persistence & File Management - Context
+
+**Gathered:** 2026-03-12
+**Status:** Ready for planning
+
+<domain>
+## Phase Boundary
+
+CSV data logging to flash memory with file management UI. User can view list of CSV files, navigate/scroll through files, view file contents, delete files, and generate tidEDA formatted files for transmission to myvscada server.
+
+</domain>
+
+<decisions>
+## Implementation Decisions
+
+### Storage Location
+- CSV files stored in `/myvscada/logger` (matches server folder structure)
+
+### File Naming
+- Format: `SP{station_id}_{timestamp}.csv` (e.g., `SP001_20260312_143022.csv`)
+
+### tidEDA Format
+- Standard format — matches existing system specification
+
+### Logging Trigger
+- Periodic interval — configurable logging interval (e.g., every 5/10/15 minutes)
+
+### OpenCode's Discretion
+- Exact logging interval default value
+- File retention policy (how many files to keep)
+- Scroll behavior (smooth scroll vs page-by-page)
+
+</decisions>
+
+<code_context>
+## Existing Code Insights
+
+### Reusable Assets
+- Flask backend already running (src/app.py) — extend with file API routes
+- Settings stored via existing settings API
+- Bootstrap 5.3 templates — can reuse for file list UI
+
+### Established Patterns
+- Socket.IO for real-time updates — can use for file list refresh
+- RESTful API structure — follow same pattern for file endpoints
+- Touch-optimized UI — apply same 48px+ touch targets
+
+### Integration Points
+- New file API routes: `/api/files`, `/api/files/<name>`, `/api/files/<name>/delete`
+- New "Flash Memory" menu link in main navigation
+- Reuse calibration template structure for file list
+
+</code_context>
+
+<specifics>
+## Specific Ideas
+
+- `/myvscada/logger` path matches the server directory structure in protocol settings
+- File naming matches existing convention from THE_IDEA.md (SP8020_FTP.txt style)
+- Standard tidEDA format per existing system specification
+
+</specifics>
+
+<deferred>
+## Deferred Ideas
+
+None — discussion stayed within phase scope
+
+</deferred>
+
+---
+
+*Phase: 02-data-persistence-file-management*
+*Context gathered: 2026-03-12*