docs(01): capture phase context

Phase 01: Foundation
- Implementation decisions documented
- Phase boundary established

.planning/phases/01-foundation/01-CONTEXT.md

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+# Phase 1: Foundation - Context
+
+**Gathered:** 2026-01-28
+**Status:** Ready for planning
+
+<domain>
+## Phase Boundary
+
+Basic Telegram ↔ n8n communication working. Set up Telegram bot via BotFather, create n8n workflow with Telegram trigger, verify message round-trip with echo, and implement user ID authentication. This phase delivers REQ-01 (send/receive messages) and REQ-09 (user ID auth).
+
+</domain>
+
+<decisions>
+## Implementation Decisions
+
+### Bot personality & responses
+- Tone: Claude's discretion — pick what feels natural for each response
+- Formatting: Use Telegram formatting (bold for names, code blocks for logs, etc.)
+- Emojis: Claude's discretion — use where they add clarity
+- Error messages: Include technical details ("Couldn't start Plex: container already running")
+
+### Authentication behavior
+- Unauthorized users: Silent ignore — no response, bot appears offline to strangers
+- User ID config: Environment variable in n8n — easy to change without editing workflow
+- Logging: Optional for troubleshooting, but default to silent ignore
+
+### Message handling
+- Command style: Both slash commands (/status) AND natural language ("how's plex?") work
+- Unknown messages: Claude's discretion on how to handle misunderstandings
+- No /help command — keep it minimal, figure it out from conversation
+- Echo test: Include metadata — "Got: [message]" + timestamp to confirm processing
+
+### Claude's Discretion
+- Exact tone and personality of responses
+- Emoji usage (use where helpful)
+- How to handle misunderstood messages
+
+</decisions>
+
+<specifics>
+## Specific Ideas
+
+- Echo test should include timestamp to prove the message was processed, not just reflected
+- Bot should feel like messaging a knowledgeable friend, not a rigid command interface
+
+</specifics>
+
+<deferred>
+## Deferred Ideas
+
+None — discussion stayed within phase scope
+
+</deferred>
+
+---
+
+*Phase: 01-foundation*
+*Context gathered: 2026-01-28*