feat: Agent capacity policy Create/Edit pages (#12424)

# Pull Request Template

## Description

Fixes
https://linear.app/chatwoot/issue/CW-5573/feat-createedit-agent-capacity-policy-page

## Type of change

- [x] New feature (non-breaking change which adds functionality)

## How Has This Been Tested?

### Loom video

https://www.loom.com/share/8de9e3c5d8824cd998d242636540dd18?sid=1314536f-c8d6-41fd-8139-cae9bf94f942

### Screenshots

**Light mode**
<img width="1666" height="1225" alt="image"
src="https://github.com/user-attachments/assets/7e6d83a4-ce02-47a7-91f6-87745f8f5549"
/>
<img width="1666" height="1225" alt="image"
src="https://github.com/user-attachments/assets/7dd1f840-2e25-4365-aa1d-ed9dac13385a"
/>

**Dark mode**
<img width="1666" height="1225" alt="image"
src="https://github.com/user-attachments/assets/0c787095-7146-4fb3-a61a-e2232973bcba"
/>
<img width="1666" height="1225" alt="image"
src="https://github.com/user-attachments/assets/481c21fd-03b5-4c1f-b59e-7f8c8017f9ce"
/>


## Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [x] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules

---------

Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>

app/javascript/dashboard/i18n/locale/en/settings.json

@@ -579,6 +579,92 @@
         },
         "NO_RECORDS_FOUND": "No agent capacity policies found"
       },
+      "CREATE": {
+        "HEADER": {
+          "TITLE": "Create agent capacity policy"
+        },
+        "CREATE_BUTTON": "Create policy",
+        "API": {
+          "SUCCESS_MESSAGE": "Agent capacity policy created successfully",
+          "ERROR_MESSAGE": "Failed to create agent capacity policy"
+        }
+      },
+      "EDIT": {
+        "HEADER": {
+          "TITLE": "Edit agent capacity policy"
+        },
+        "EDIT_BUTTON": "Update policy",
+        "CONFIRM_ADD_AGENT_DIALOG": {
+          "TITLE": "Add agent",
+          "DESCRIPTION": "{agentName} is already linked to another policy. Are you sure you want to link it to this policy? It will be unlinked from the other policy.",
+          "CONFIRM_BUTTON_LABEL": "Continue",
+          "CANCEL_BUTTON_LABEL": "Cancel"
+        },
+        "API": {
+          "SUCCESS_MESSAGE": "Agent capacity policy updated successfully",
+          "ERROR_MESSAGE": "Failed to update agent capacity policy"
+        },
+        "AGENT_API": {
+          "ADD": {
+            "SUCCESS_MESSAGE": "Agent added to policy successfully",
+            "ERROR_MESSAGE": "Failed to add agent to policy"
+          },
+          "REMOVE": {
+            "SUCCESS_MESSAGE": "Agent removed from policy successfully",
+            "ERROR_MESSAGE": "Failed to remove agent from policy"
+          }
+        }
+      },
+      "FORM": {
+        "NAME": {
+          "LABEL": "Policy name:",
+          "PLACEHOLDER": "Enter policy name"
+        },
+        "DESCRIPTION": {
+          "LABEL": "Description:",
+          "PLACEHOLDER": "Enter description"
+        },
+        "INBOX_CAPACITY_LIMIT": {
+          "LABEL": "Inbox capacity limits",
+          "ADD_BUTTON": "Add inbox",
+          "FIELD": {
+            "SELECT_INBOX": "Select inbox",
+            "MAX_CONVERSATIONS": "Max conversations",
+            "SET_LIMIT": "Set limit"
+          },
+          "EMPTY_STATE": "No inbox limit set"
+        },
+        "EXCLUSION_RULES": {
+          "LABEL": "Exclusion rules",
+          "DESCRIPTION": "Conversations that satisfy the following conditions would not count towards agent capacity",
+          "TAGS": {
+            "LABEL": "Exclude conversations tagged with specific labels",
+            "ADD_TAG": "add tag",
+            "DROPDOWN": {
+              "SEARCH_PLACEHOLDER": "Search and select tags to add"
+            },
+            "EMPTY_STATE": "No tags added to this policy."
+          },
+          "DURATION": {
+            "LABEL": "Exclude conversations older than a specified duration",
+            "PLACEHOLDER": "Set time"
+          }
+        },
+        "USERS": {
+          "LABEL": "Assigned agents",
+          "DESCRIPTION": "Add agents for which this policy will be applicable.",
+          "ADD_BUTTON": "Add agent",
+          "DROPDOWN": {
+            "SEARCH_PLACEHOLDER": "Search and select agents to add",
+            "ADD_BUTTON": "Add"
+          },
+          "EMPTY_STATE": "No agents added",
+          "API": {
+            "SUCCESS_MESSAGE": "Agent successfully added to policy",
+            "ERROR_MESSAGE": "Failed to add agent to policy"
+          }
+        }
+      },
       "DELETE_POLICY": {
         "SUCCESS_MESSAGE": "Agent capacity policy deleted successfully",
         "ERROR_MESSAGE": "Failed to delete agent capacity policy"