fix(globe-wallet): enforce timelock on spend limit increases to protect against compromised keys (issue #83)

README.md

@@ -72,6 +72,10 @@ get_assets(env, user) -> Vec<AssetInfo>
 
 // Spend limits
 set_spend_limit(env, user, asset_code, limit: i128) -> Result<()>
+propose_spend_limit_increase(env, user, asset_code, limit: i128, delay_in_ledgers: u32) -> Result<()>
+execute_spend_limit_increase(env, user, asset_code) -> Result<()>
+cancel_spend_limit_increase(env, user, asset_code) -> Result<()>
+get_spend_limit_proposal(env, user, asset_code) -> Option<SpendLimitProposal>
 get_spend_limit(env, user, asset_code) -> i128
 record_spend(env, user, asset_code, amount) -> Result<()>
 ```
@@ -80,6 +84,9 @@ record_spend(env, user, asset_code, amount) -> Result<()>
 
 - Limit is per-user, per-asset, daily (86 400-second window from ledger timestamp).
 - `limit = 0` means unlimited.
+- **Asymmetric Limit Modifications & Compromised-Key Defense:**
+  - Lowering an existing limit or establishing an initial cap is applied **instantly** via `set_spend_limit` (with retroactive enforcement ensuring today's spend doesn't already exceed the new cap).
+  - Raising an existing limit or removing an active cap (`limit = 0`) cannot be done instantly via `set_spend_limit` (rejected with `SpendLimitIncreaseRequiresProposal`). It requires proposing the increase with a minimum timelock delay (`MIN_SPEND_LIMIT_INCREASE_DELAY = 17_280` ledgers / ~24 hours) via `propose_spend_limit_increase`, waiting for the timelock window, and calling `execute_spend_limit_increase`. This defends against the compromised-key threat model by ensuring an attacker with valid user signatures cannot raise the limit and drain funds in a single transaction or session without giving the owner time to cancel (`cancel_spend_limit_increase`).
 - `record_spend` is called from any payment path; rejects with `SpendLimitExceeded` if
   cumulative daily spend would exceed the limit.
 - Day window resets automatically — no manual reset required.

contracts/globe-wallet/test_snapshots/tests/test_accept_by_wrong_address_fails.1.json

@@ -97,7 +97,7 @@
             },
             "ext": "v0"
           },
-          4095
+          518400
         ]
       ],
       [
@@ -151,7 +151,7 @@
             },
             "ext": "v0"
           },
-          4095
+          518400
         ]
       ]
     ]
@@ -348,7 +348,7 @@
             ],
             "data": {
               "error": {
-                "contract": 3
+                "contract": 1003
               }
             }
           }
@@ -369,7 +369,7 @@
               },
               {
                 "error": {
-                  "contract": 3
+                  "contract": 1003
                 }
               }
             ],
@@ -394,7 +394,7 @@
               },
               {
                 "error": {
-                  "contract": 3
+                  "contract": 1003
                 }
               }
             ],

contracts/globe-wallet/test_snapshots/tests/test_add_and_get_assets.1.json

@@ -219,7 +219,7 @@
             },
             "ext": "v0"
           },
-          4095
+          518400
         ]
       ],
       [
@@ -306,7 +306,7 @@
             },
             "ext": "v0"
           },
-          4095
+          518400
         ]
       ]
     ]
@@ -662,4 +662,4 @@
       "failed_call": false
     }
   ]
-}
+}

contracts/globe-wallet/test_snapshots/tests/test_add_and_list_guardians.1.json

@@ -118,6 +118,43 @@
                           "address": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAFCT4"
                         }
                       },
+                      {
+                        "key": {
+                          "vec": [
+                            {
+                              "symbol": "GuardianMembership"
+                            }
+                          ]
+                        },
+                        "val": {
+                          "map": [
+                            {
+                              "key": {
+                                "address": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAHK3M"
+                              },
+                              "val": {
+                                "bool": true
+                              }
+                            },
+                            {
+                              "key": {
+                                "address": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAITA4"
+                              },
+                              "val": {
+                                "bool": true
+                              }
+                            },
+                            {
+                              "key": {
+                                "address": "CAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAK3IM"
+                              },
+                              "val": {
+                                "bool": true
+                              }
+                            }
+                          ]
+                        }
+                      },
                       {
                         "key": {
                           "vec": [
@@ -147,7 +184,7 @@
             },
             "ext": "v0"
           },
-          4095
+          518400
         ]
       ],
       [
@@ -267,7 +304,7 @@
             },
             "ext": "v0"
           },
-          4095
+          518400
         ]
       ]
     ]