Add tests for per-mission DrawTool file isolation (#1094) #1125

Summary

#1094 scoped DrawTool files by mission (user_files.mission column, mission param on /api/draw/files/getfiles, /make, /change, and per-mission showNullMissionFiles / showMasterFiles DrawTool variables). It shipped without automated tests. This issue covers the test coverage needed to verify cross-mission isolation and close out JIRA IDS-10388 for D56.

Tests to add

/getfiles

• File created under mission A is not returned when querying with mission: B
• File created under mission A is returned when querying with mission: A
• Legacy files (mission = NULL) are returned when showNullMissionFiles is unset/true, and excluded when false
• Master files (is_master = true) are returned when showMasterFiles is unset/true, and excluded when false (including master files belonging to the same mission)
• Unknown mission returns status: "failure" ("Unknown mission")
• Private files of another user remain hidden regardless of mission (existing file_owner/public filter still applies)
• Document/assert behavior when mission is omitted (currently returns files from all missions, so isolation depends on the client sending mission)

/make

• mission is persisted on the new file
• Unknown mission is rejected
• Omitted mission creates a NULL-mission (legacy) file

/change

• A lead (mmgis-group) can move a file to another existing mission
• A non-lead cannot change a file's mission
• Moving to an unknown mission is rejected

Migration / legacy data

• ALTER TABLE ... ADD COLUMN IF NOT EXISTS mission is idempotent on user_files and user_files_tests, and pre-existing rows come through as mission = NULL and stay visible by default

Frontend

• DrawTool sends the current mission on getfiles/make (Playwright: create a file in mission A, switch to mission B, confirm it isn't listed)

Notes

• Use the mmgis-test DB per the test-safety rules in AGENTS.md.
• Two test missions with different DrawTool variables can be set up in tests/global-setup.js (it was already touched by DrawTool: scope files by mission with per-mission legacy/master visibility toggles #1094).

Refs: #1094 · JIRA IDS-10388 (D56)