Support running ephemeral commands (#543)

* initial

* save work, starting to add backend types

* save work

* save work

* Add EphemeralWriteCloser

* Command pipes thru, triggers infinite loop

* save debugging

* fix bad merge

* save debug statements

* fixing spaghetti

* clean up code

* got cwd override working

* Add separate paths for stdout and stderr writers

* fix stdout/stderr

* env vars are now working

* revert waveshell changes

* Making EphemeralWriteCloser into a more generic BufferedPipe

* formatting

* comment

* delete unused package

* more naming changes

* add package comment

* add UsePty to EphemeralRunOpts

* document UsePty

* ensure only one downstream writer can read from the buffer

* store pointer to syncs

* remove inshellisense stuff for now

* remove debugs

* revert yarn

* remove unnecessary debugs in main-server

* more debugging removed

* revert tsconfig

waveshell/pkg/packet/packet.go

@@ -820,7 +820,7 @@ type RunPacketType struct {
 	State         *ShellState     `json:"state,omitempty"`
 	StatePtr      *ShellStatePtr  `json:"stateptr,omitempty"`      // added in Wave v0.7.2
 	StateComplete bool            `json:"statecomplete,omitempty"` // set to true if state is complete (the default env should not be set)
-	UsePty        bool            `json:"usepty,omitempty"`
+	UsePty        bool            `json:"usepty,omitempty"`        // Set to true if the command should be run in a pty. This will write all output to the stdout file descriptor with PTY formatting.
 	TermOpts      *TermOpts       `json:"termopts,omitempty"`
 	Fds           []RemoteFd      `json:"fds,omitempty"`
 	RunData       []RunDataType   `json:"rundata,omitempty"`