feat: wiki toggle via env var (Approach A)

[jeff-r2026]

Summary

Approach A: Environment Variable — The simplest, zero-config approach.

• Add TEAMAI_WIKI_DISABLED=1 env var to disable the built-in wiki feature
• Prevents conflicts with third-party team-wiki plugins (e.g. team-wiki)
• No schema changes, no config file modifications needed

How to disable:

export TEAMAI_WIKI_DISABLED=1
# or
export TEAMAI_WIKI_ENABLED=false

When disabled:

• Wiki resources skipped during teamai pull / teamai push
• teamai-wiki builtin skill not deployed
• teamai status shows wiki disabled hint

Trade-offs:

Pros	Cons
Zero config overhead	Not persisted across shells (unless in .bashrc)
Works immediately	No team-level control
No migration needed	Not visible in config files

Test plan

• isWikiEnabled() returns true by default
• Returns false with TEAMAI_WIKI_DISABLED=1
• Returns false with TEAMAI_WIKI_ENABLED=false
• All 942 existing tests pass
• TypeScript compiles cleanly

Closes #21

💡 This is 1 of 3 alternative implementations. See also:

• Approach B: Local config (feat/wiki-toggle-local-config)
• Approach C: Team config + local override (feat/wiki-toggle-team-config)