Add mobile services, web proxy, and Gemma4 agent loop

- Mobile: add push notification and calendar sync services with full test suite (calendar, eventStore, notifications,
  screens)
- Mobile: add EAS build config and Jest setup
- Web: add API proxy, update useDestinationStation/useJourneys hooks, add middleware tests
- Web: update next.config and rebuild
- Agent: add Gemma4-based agent loop (agent_base, ttl_agent, ts_agent)
- Docs: add privacy policy, post-MVP plan, and aider rules

AIDER_RULES.md

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+# Aider Coding Rules
+
+  You are editing a real repository. Correctness is more important than speed.
+
+  ## Operating Rules
+
+  1. Before editing, identify the exact requested task and restate the concrete files or behaviors that must
+change.
+  2. Read the relevant existing files before making changes. Do not infer APIs, imports, types, or component
+contracts from memory.
+  3. Implement every requested step. Do not skip checklist items, tests, wiring, exports, or documentation
+updates that are part of the task.
+  4. Keep changes minimal and scoped. Do not refactor unrelated code, rename unrelated symbols, or change
+behavior outside the task.
+  5. Prefer existing project patterns over new abstractions.
+  6. If a requirement is ambiguous, choose the smallest implementation that satisfies the written request and
+state the assumption.
+
+  ## Code Quality Rules
+
+  1. Do not introduce type errors, broken imports, missing exports, unused variables, or dead code.
+  2. Do not use placeholder code, TODOs, stubs, fake implementations, or comments claiming work is done when
+it is not.
+  3. Preserve existing public APIs unless the task explicitly changes them.
+  4. Handle null, undefined, empty arrays, failed network calls, and invalid user input where relevant.
+  5. Keep async behavior explicit. Await promises that must complete before continuing.
+  6. Do not weaken or delete tests to make checks pass.
+
+  ## Step Completion Rules
+
+  Before finishing, verify this checklist mentally and fix any failures:
+
+  - The requested behavior is fully implemented.
+  - Every required file is created or updated.
+  - All changed imports resolve.
+  - All changed types are valid.
+  - Existing behavior not mentioned in the task is preserved.
+  - Tests were added or updated when behavior changed.
+  - No generated files, build artifacts, cache files, or secrets were edited.
+  - The final response lists what changed and any checks that still need to be run.
+
+  ## If You Are Unsure
+
+  Do not guess. Inspect the repository first. If still uncertain, make the smallest safe change and
+explicitly mention the assumption in the final response.