feat: Add historical context files for team members and update project documentation with Slack archive import details

ai/context/people/tim-longfield.md

@@ -0,0 +1,20 @@
+# Tim Longfield
+
+## Role
+
+FTPlanning-side collaborator relevant to cross-framework issue ownership.
+
+---
+
+## Known Context
+
+- Appeared when issues first thought to be XFlow bugs were traced into FTPlanning
+- Relevant contact for whether a transfer/add-money bug belonged to FTPlanning instead of XFlow
+- Useful when a consumer-side framework fix was needed before XFlow could close validation work
+
+---
+
+## Guidance
+
+- Treat Tim as a relevant contact for FTPlanning-owned fixes and cross-team validation
+- If future context clarifies the formal role/team, update this file directly