fix: filter DA2/DA3 terminal responses to prevent '1;10;0c' display in tmux

When entering or refreshing a webterm session running tmux, the text '1;10;0c'
was appearing on screen. This was caused by tmux sending a DA2 (Secondary Device
Attributes) query (ESC[>c) to detect terminal capabilities.

The filtering code only handled DA1 responses (ESC[?...c) but not DA2 (ESC[>...c)
or DA3 (ESC[=...c) responses. Updated the regex patterns to match all three variants:

- DA1 (Primary): ESC[?...c - already worked
- DA2 (Secondary): ESC[>...c - now fixed (tmux uses this)
- DA3 (Tertiary): ESC[=...c - added for completeness

The fix applies to:
- Live terminal output filtering
- Replay buffer filtering on reconnect
- Partial escape sequence buffering

All 342 tests pass with the updated patterns.

src/webterm/docker_exec_session.py

@@ -29,14 +29,17 @@ DEFAULT_SCREEN_WIDTH = 132
 DEFAULT_SCREEN_HEIGHT = 45
 
 # Pattern to filter out terminal device attribute responses that cause display issues
-# These are responses to queries that shouldn't be displayed as text.
+# These are responses to DA1/DA2/DA3 queries that shouldn't be displayed as text
-# Matches complete DA1/DA2 responses like \x1b[?1;10;0c or \x1b[?64;1;2;...c
+# Matches complete responses like:
-DA_RESPONSE_PATTERN = re.compile(rb"\x1b\[\?[\d;]+c")
+#   \x1b[?1;10;0c  (DA1 - Primary Device Attributes)
+#   \x1b[>1;10;0c  (DA2 - Secondary Device Attributes, sent by tmux)
+#   \x1b[=1;0c     (DA3 - Tertiary Device Attributes)
+DA_RESPONSE_PATTERN = re.compile(rb"\x1b\[[?>=][\d;]*c")
 
 # Pattern to detect partial DA responses at end of data (incomplete escape sequence)
-# Matches: \x1b, \x1b[, \x1b[?, \x1b[?1, \x1b[?1;, \x1b[?1;10, etc.
+# Matches: \x1b, \x1b[, \x1b[?, \x1b[>, \x1b[=, \x1b[?1, \x1b[>1;10, etc.
 # These need to be held back until more data arrives to see if they complete
-DA_PARTIAL_PATTERN = re.compile(rb"\x1b(?:\[(?:\?[\d;]*)?)?$")
+DA_PARTIAL_PATTERN = re.compile(rb"\x1b(?:\[(?:[?>=][\d;]*)?)?$")
 
 
 @dataclass(frozen=True)

src/webterm/local_server.py

@@ -27,10 +27,11 @@ from .session_manager import SessionManager
 from .svg_exporter import render_terminal_svg
 from .types import Meta, RouteKey, SessionID
 
-# Pattern to filter terminal device attribute responses (DA1/DA2) from replay buffer.
+# Pattern to filter terminal device attribute responses (DA1/DA2/DA3) from replay buffer.
 # These responses can appear as visible text like "1;10;0c" if split across reads.
+# Matches: \x1b[?...c (DA1), \x1b[>...c (DA2 from tmux), \x1b[=...c (DA3)
 # See docker_exec_session.py and terminal_session.py for main filtering.
-DA_RESPONSE_PATTERN = re.compile(rb"\x1b\[\?[\d;]+c")
+DA_RESPONSE_PATTERN = re.compile(rb"\x1b\[[?>=][\d;]*c")
 
 if TYPE_CHECKING:
     from .config import Config

src/webterm/terminal_session.py

@@ -33,13 +33,16 @@ DEFAULT_SCREEN_WIDTH = 132
 DEFAULT_SCREEN_HEIGHT = 45
 
 # Pattern to filter out terminal device attribute responses that cause display issues
-# These are responses to DA1/DA2 queries that shouldn't be displayed as text
+# These are responses to DA1/DA2/DA3 queries that shouldn't be displayed as text
-# Matches complete responses like \x1b[?1;10;0c or \x1b[?64;1;2;...c
+# Matches complete responses like:
-DA_RESPONSE_PATTERN = re.compile(rb"\x1b\[\?[\d;]+c")
+#   \x1b[?1;10;0c  (DA1 - Primary Device Attributes)
+#   \x1b[>1;10;0c  (DA2 - Secondary Device Attributes, sent by tmux)
+#   \x1b[=1;0c     (DA3 - Tertiary Device Attributes)
+DA_RESPONSE_PATTERN = re.compile(rb"\x1b\[[?>=][\d;]*c")
 
 # Pattern to detect partial DA responses at end of data (incomplete escape sequence)
-# Matches: \x1b, \x1b[, \x1b[?, \x1b[?1, \x1b[?1;, etc.
+# Matches: \x1b, \x1b[, \x1b[?, \x1b[>, \x1b[=, \x1b[?1, \x1b[>1;10, etc.
-DA_PARTIAL_PATTERN = re.compile(rb"\x1b(?:\[(?:\?[\d;]*)?)?$")
+DA_PARTIAL_PATTERN = re.compile(rb"\x1b(?:\[(?:[?>=][\d;]*)?)?$")
 
 
 class TerminalSession(Session):