docs: align engine terminology in telegram and docs (#162)

docs/tutorials/conversation-modes.md

@@ -38,7 +38,7 @@ To pin a project or branch for the chat, use:
 
 `/new` clears the session but keeps the bound context.
 
-Tip: set a default agent for this chat with `/agent set claude`.
+Tip: set a default engine for this chat with `/agent set claude`.
 
 ## Stateless (reply-to-continue)
 

docs/tutorials/first-run.md

@@ -19,7 +19,7 @@ Takopi keeps running in your terminal. In Telegram, your bot will post a startup
     🐙 takopi is ready
 
     default: codex<br>
-    agents: codex, claude<br>
+    engines: codex, claude<br>
     projects: none<br>
     mode: chat<br>
     topics: disabled<br>
@@ -29,7 +29,7 @@ Takopi keeps running in your terminal. In Telegram, your bot will post a startup
 The engines/projects list reflects your setup. This tells you:
 
 - Which engine is the default
-- Which agents are available (and any missing ones)
+- Which engines are available (and any missing ones)
 - Which projects are registered
 - Which directory Takopi will run in
 
@@ -131,7 +131,7 @@ If a resume token was already issued (and resume lines are enabled), it will sti
 
 ## 7. Try a different engine
 
-Want to use a different agent for one message? Prefix your message with `/<engine>`:
+Want to use a different engine for one message? Prefix your message with `/<engine>`:
 
 !!! user "You"
     /claude explain the error handling in this codebase

docs/tutorials/install.md

@@ -228,9 +228,9 @@ Once Takopi receives your message:
 Takopi scans your PATH for installed agent CLIs:
 
 ```
-step 4: default agent
+step 4: default engine
 
-takopi runs these agents on your computer. switch anytime with /agent.
+takopi runs these engines on your computer. switch anytime with /agent.
 
   engine    status         install command
   ───────────────────────────────────────────
@@ -239,7 +239,7 @@ takopi runs these agents on your computer. switch anytime with /agent.
   opencode  ✗ not found    npm install -g opencode-ai@latest
   pi        ✗ not found    npm install -g @mariozechner/pi-coding-agent
 
-? choose default agent:
+? choose default engine:
  ❯ codex
    claude
 ```

docs/tutorials/multi-engine.md

@@ -1,14 +1,14 @@
 # Multi-engine workflows
 
-This tutorial shows you how to use different agents for different tasks and set up defaults so you don't have to think about it.
+This tutorial shows you how to use different engines for different tasks and set up defaults so you don't have to think about it.
 
-**What you'll learn:** Engine directives, persistent defaults, and when to use which agent.
+**What you'll learn:** Engine directives, persistent defaults, and when to use which engine.
 
 ## Why multiple engines?
 
-Different agents have different strengths:
+Different engines have different strengths:
 
-| Agent | Good at |
+| Engine | Good at |
 |-------|---------|
 | **Codex** | Fast edits, shell commands, quick fixes |
 | **Claude Code** | Complex refactors, architecture, long context |
@@ -65,7 +65,7 @@ Use `/agent set` to change the default for the current scope:
 Response:
 
 !!! takopi "Takopi"
-    chat default agent set to claude
+    chat default engine set to claude
 
 Now all new conversations in this chat use Claude (unless you explicitly override with `/codex`).
 
@@ -77,7 +77,7 @@ Check the current default:
 Example response:
 
 !!! takopi "Takopi"
-    agent: claude (chat default)<br>
+    engine: claude (chat default)<br>
     defaults: topic: none, chat: claude, project: none, global: codex<br>
     available: codex, claude, opencode, pi
 
@@ -89,7 +89,7 @@ Clear it:
 Response:
 
 !!! takopi "Takopi"
-    chat default agent cleared.
+    chat default engine cleared.
 
 ## 4. Defaults in topics
 

docs/tutorials/projects-and-branches.md

@@ -2,7 +2,7 @@
 
 This tutorial shows you how to register repos as projects and run tasks on feature branches without switching directories.
 
-**What you'll learn:** How to target repos from anywhere with `/project`, and run on branches with `@branch`.
+**What you'll learn:** How to target repos from anywhere with `/<project-alias>`, and run on branches with `@branch`.
 
 ## The problem
 
@@ -123,7 +123,7 @@ Replies stay on the same branch. Your main checkout is untouched.
 
 ## 5. Context persistence
 
-Once you've set a context (via `/project @branch` or by replying), it sticks:
+Once you've set a context (via `/<project-alias> @branch` or by replying), it sticks:
 
 !!! user "You"
     /happy-gadgets @feat/new-login add tests
@@ -155,7 +155,7 @@ If you mostly work in one repo, set it as the default:
     default_project = "happy-gadgets"
     ```
 
-Now messages without a `/project` prefix go to that repo:
+Now messages without a `/<project-alias>` prefix go to that repo:
 
 !!! user "You"
     add a health check endpoint