Rename Motoko entry points app.mo -> main.mo (#1471)

Aligns the entry-point filename with icp new (icp-cli-templates), mops,
the Motoko skill, and Caffeine, which all use lowercase main.mo for the
composition root (the analog of Rust's lib.rs). PascalCase remains for
exported module files (Types.mo, Counter.mo).

- git mv 35 <role>/app.mo -> <role>/main.mo across the Motoko examples
  (backend/, plus caller/callee, publisher/subscriber for multi-canister).
- Update mops.toml [canisters.*] main = paths and their comments.
- Update all doc/code references: AGENTS.md (structure, mops snippet,
  naming rule), example READMEs (hello_world, icrc2-swap, llm_chatbot,
  parallel_calls, pub-sub, threshold-ecdsa, threshold-schnorr,
  unity_ii_deeplink), and an icrc.did comment.

Verified: mops check passes for hello_world and the multi-canister
parallel_calls / pub-sub (both --actor-env-alias). who_am_i already used
main.mo. Closes #1463.

Author: marc0olo

AGENTS.md

@@ -11,4 +11,4 @@ core = "2.5.0"
 args = ["--default-persistent-actors", "-W=M0236,M0237,M0223"]
 
 [canisters.backend]
-main = "backend/app.mo"
+main = "backend/main.mo"

motoko/backend_only/backend/app.mo motoko/backend_only/backend/main.momotoko/backend_only/backend/app.mo renamed to motoko/backend_only/backend/main.mo

@@ -10,4 +10,4 @@ ic = "4.0.0"
 args = [ "--default-persistent-actors", "-W=M0236,M0237,M0223" ]
 
 [canisters.backend]
-main = "backend/app.mo"
+main = "backend/main.mo"

motoko/backend_only/mops.toml

@@ -12,4 +12,4 @@ ic = "4.0.0"
 args = ["--default-persistent-actors", "-W=M0236,M0237,M0223"]
 
 [canisters.backend]
-main = "backend/app.mo"
+main = "backend/main.mo"

motoko/basic_bitcoin/backend/app.mo motoko/basic_bitcoin/backend/main.momotoko/basic_bitcoin/backend/app.mo renamed to motoko/basic_bitcoin/backend/main.mo

@@ -12,4 +12,4 @@ ic = "4.0.0"
 args = ["--default-persistent-actors", "-W=M0236,M0237,M0223"]
 
 [canisters.backend]
-main = "backend/app.mo"
+main = "backend/main.mo"