test: add e2e test suite and fix namespace/mention/assignee flags

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

README.md

@@ -79,6 +79,9 @@ Update a node.
 | `--title` | New title |
 | `--status` | New status |
 | `--prio` | New priority |
+| `--type` | New type |
+| `--namespace` | New namespace |
+| `--assignee` | New assignee |
 | `--due` | New due date |
 | `--clear-due` | Clear due date |
 | `--content` | New content |
@@ -103,6 +106,7 @@ Query and list nodes.
 | `--namespace` | Filter by namespace |
 | `--tag` | Filter by tag (repeatable) |
 | `--assignee` | Filter by assignee |
+| `--mention` | Filter by mention |
 
 ### `ax edit <id>`
 
@@ -128,9 +132,8 @@ ax alias del mywork             # delete alias
 
 | Alias | Command | Description |
 |-------|---------|-------------|
-| `mine` | `list --assignee $me --tag _status::open` | Show open tasks assigned to you |
-| `due` | `list --tag _status::open --tag _due` | Show open tasks with due dates |
-| `new` | `add $@` | Create a new task |
+| `mine` | `list --assignee $me --type issue --status open` | Show open issues assigned to you |
+| `due` | `list --type issue --status open` | Show open issues |
 | `inbox` | `list --mention $me` | Show your inbox |
 
 **Alias argument expansion:**
@@ -151,23 +154,23 @@ ax find backend open  # expands to: list --tag backend --status open
 
 Relations connect nodes together:
 
-| Type | Direction | Behavior |
-|------|-----------|----------|
-| `blocks` | issue → issue | Prevents closing until blocker is done |
-| `subtask` | issue → issue | Shows as tree under parent |
-| `related` | any ↔ any | Shown in related section |
-| `assignee` | issue → user | Adds to user's inbox |
-| `in_namespace`| any → namespace | Groups nodes by project or team |
+| Type | Meaning | Behavior |
+|------|---------|----------|
+| `blocks` | A blocks B — B can't close until A is done | Enforced on status=done |
+| `subtask` | A is a subtask of B | |
+| `related` | A is related to B | |
+| `assignee` | A is assigned to user | Single-value; set via `--assignee` flag |
+| `in_namespace` | A belongs to namespace | Single-value; set via `--namespace` flag |
 
 ```bash
-# Create subtask
-ax add "Write tests" --rel subtask:abc12
-
-# Block an issue
-ax add "Fix login" --rel blocks:def34
+# Block an issue (B can't close until A is done)
+ax update A --rel blocks:B
 
 # Assign to user
-ax update abc12 --rel assignee:alice
+ax update abc12 --assignee alice
+
+# Create subtask
+ax update abc12 --rel subtask:parent12
 ```
 
 ## Tags and Properties