docs(phase-3): capture phase context

.planning/phases/03-network-transmission/03-CONTEXT.md

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+# Phase 3: Network Transmission - Context
+
+**Gathered:** 2026-03-12
+**Status:** Ready for planning
+
+<domain>
+## Phase Boundary
+
+Automatic CSV data transmission to myvscada server with protocol configuration. User can configure server connection settings (FTP, SCP, SFTP, or WebDAV protocol), system transmits CSV data files automatically, and transmission status is visible in the UI.
+
+</domain>
+
+<decisions>
+## Implementation Decisions
+
+### Protocols
+- Support all four protocols: FTP, SFTP, SCP, WebDAV
+- Settings already exist (SETT-09) — integrate with existing protocol settings UI
+
+### Scheduling
+- Scheduled transmission at configurable times (e.g., daily at specific hour)
+- User configures schedule in Settings
+
+### Error Handling
+- Retry 3 times on transmission failure
+- Log errors for debugging
+- Show error status in UI
+
+### Status Display
+- Basic status: success/fail with timestamp
+- Show last transmission result on dashboard
+
+### OpenCode's Discretion
+- Exact schedule default times
+- Retry interval timing
+- UI placement of status indicator
+
+</decisions>
+
+<a
+## Existing Code Insights
+
+### Reusable Assets
+- Existing SETT-09 (Protocol settings) in requirements — build on that
+- Flask backend already running — add transmission endpoints
+- Bootstrap 5.3 templates — reuse for status UI
+
+### Established Patterns
+- Socket.IO for real-time updates — can push transmission status
+- Settings API structure — follow same pattern for transmission config
+- Touch-optimized UI — same 48px+ touch targets
+
+### Integration Points
+- Protocol settings already exist in Settings UI
+- File export from Phase 2 — transmit exported tidEDA files
+- Dashboard can show transmission status indicator
+
+</code_context>
+
+<specifics>
+## Specific Ideas
+
+- Transmission scheduled at user-configured times (e.g., 07:00 and 17:00 like tide data)
+- Files to transmit: tidEDA formatted files from /myvscada/logger
+
+</specifics>
+
+<deferred>
+## Deferred Ideas
+
+None — discussion stayed within phase scope
+
+</deferred>
+
+---
+
+*Phase: 03-network-transmission*
+*Context gathered: 2026-03-12*