Stop mislabeling truncated captures as "exact"

internal/proxy/tee.go's teeConn silently drops bytes past
maxCaptureBytes (10 MiB) but callers unconditionally marked the result
"exact" anyway. Confirmed live: proxying a 15 MiB response worked
correctly end-to-end (the client got the full, real 15 MiB - proxying
itself is unbounded, only storage is capped), but the stored history
entry was exactly 10485760 bytes with response_exact=1 still set. For a
tool whose core value proposition is "raw bytes are the source of
truth," a silently truncated capture presented as complete could hide
the very evidence a smuggling or parser-differential investigation is
looking for in the tail of a large body - and give false confidence
that it isn't there.

teeConn.Take() now returns (data, truncated) instead of just data;
truncated is true whenever a Read had to drop bytes because the buffer
was already at cap. Every caller (proxy.go's forward() on both the
request and response side, repeat.go's sendRaw for Repeater/Intruder)
now folds truncated into exact - a truncated capture is never marked
exact - and additionally threads a distinct RequestTruncated/
ResponseTruncated bool through store.Entry, ipc.EntryDetail, and the
TUI, since "truncated" and "reconstructed" (HTTP/2, which never had
wire-exact bytes to begin with) are different situations worth telling
apart: a truncated capture is still real wire bytes, just incomplete,
not a synthesized reconstruction. The detail/repeater views now show
"truncated (hit capture size limit)" specifically rather than lumping
it in with "reconstructed", which would have implied more
transformation happened than actually did.

Schema: history gains request_truncated/response_truncated columns via
the same ALTER-TABLE-and-ignore-duplicate-column pattern already used
for source/flagged, so existing databases upgrade in place.

Verified live: a target server returning a 15 MiB body (over the 10 MiB
cap) proxied through cleanly - full body reached the client - while the
stored entry shows length=10485760, response_exact=0,
response_truncated=1 (previously would have shown response_exact=1);
the TUI's Detail view correctly displays "Response (10485760 bytes,
truncated (hit capture size limit))" instead of "exact".

go build/vet/gofmt/test/mod tidy all clean.

1 files changed, 20 insertions, 18 deletions

diff --git a/internal/proxy/repeat.go b/internal/proxy/repeat.go
index 3ee7cea..f682b99 100644
--- a/internal/proxy/repeat.go
+++ b/internal/proxy/repeat.go
@@ -38,7 +38,7 @@ func (s *Server) sendRaw(ctx context.Context, scheme, host string, raw []byte, s
 
 	conn, err := dialForRepeat(ctx, scheme, host)
 	if err != nil {
-		return s.recordRaw(started, time.Since(started), scheme, host, method, path, raw, nil, 0, err.Error(), source)
+		return s.recordRaw(started, time.Since(started), scheme, host, method, path, raw, nil, false, false, 0, err.Error(), source)
 	}
 	defer conn.Close()
 	// See the matching comment in forward(): without this, a hung
@@ -48,37 +48,39 @@ func (s *Server) sendRaw(ctx context.Context, scheme, host string, raw []byte, s
 	conn.SetDeadline(time.Now().Add(upstreamTimeout))
 
 	if _, err := conn.Write(raw); err != nil {
-		return s.recordRaw(started, time.Since(started), scheme, host, method, path, raw, nil, 0, err.Error(), source)
+		return s.recordRaw(started, time.Since(started), scheme, host, method, path, raw, nil, false, false, 0, err.Error(), source)
 	}
 
 	tee := newTeeConn(conn)
 	resp, err := http.ReadResponse(bufio.NewReader(tee), &http.Request{Method: method})
 	duration := time.Since(started)
 	if err != nil {
-		return s.recordRaw(started, duration, scheme, host, method, path, raw, nil, 0, err.Error(), source)
+		return s.recordRaw(started, duration, scheme, host, method, path, raw, nil, false, false, 0, err.Error(), source)
 	}
 	defer resp.Body.Close()
 	io.Copy(io.Discard, resp.Body)
 
-	return s.recordRaw(started, duration, scheme, host, method, path, raw, tee.Take(), resp.StatusCode, "", source)
+	respRaw, truncated := tee.Take()
+	return s.recordRaw(started, duration, scheme, host, method, path, raw, respRaw, !truncated, truncated, resp.StatusCode, "", source)
 }
 
 func (s *Server) recordRaw(started time.Time, duration time.Duration, scheme, host, method, path string,
-	reqRaw, respRaw []byte, status int, errMsg, source string) (*store.Entry, error) {
+	reqRaw, respRaw []byte, respExact, respTruncated bool, status int, errMsg, source string) (*store.Entry, error) {
 	e := &store.Entry{
-		StartedAt:     started,
-		Duration:      duration,
-		Method:        method,
-		Scheme:        scheme,
-		Host:          host,
-		Path:          path,
-		StatusCode:    status,
-		RequestRaw:    reqRaw,
-		ResponseRaw:   respRaw,
-		RequestExact:  true,
-		ResponseExact: respRaw != nil,
-		Error:         errMsg,
-		Source:        source,
+		StartedAt:         started,
+		Duration:          duration,
+		Method:            method,
+		Scheme:            scheme,
+		Host:              host,
+		Path:              path,
+		StatusCode:        status,
+		RequestRaw:        reqRaw,
+		ResponseRaw:       respRaw,
+		RequestExact:      true,
+		ResponseExact:     respRaw != nil && respExact,
+		ResponseTruncated: respRaw != nil && respTruncated,
+		Error:             errMsg,
+		Source:            source,
 	}
 	if s.store != nil {
 		id, err := s.store.Insert(e)