controller v0.272.0: the backup page says when a whole-box backup does not fit (R-685); R-671, R-670, R-677

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS

controller/internal/web/backup_handlers.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"net/http"
+	"regexp"
 	"strings"
 	"time"
 
@@ -136,6 +137,28 @@ type guestTierView struct {
 	Current     bool // newest success is inside the tier's window
 	FailedAfter bool // the last attempt failed and is newer than the newest success
 	FailedAt    time.Time
+	// NoSpaceLine (v0.272.0, R-685 page half) is the plain sentence under a failed tier when the agent
+	// SKIPPED the backup because it cannot fit (agent v0.134.0+), in the reader's language.
+	NoSpaceLine string
+}
+
+// agentNoSpacePrefix is the agent's `backup.BackupSkipNoSpacePrefix` (felhom-agent v0.134.0,
+// internal/backup/runner.go) — the stable start of a tier attempt's Error when the space preflight refused.
+// A wire contract between two repos: change it in both or in neither.
+const agentNoSpacePrefix = "skipped: not enough space: "
+
+// agentNoSpaceRe reads the agent's sentence: "<target> has X GiB free; … needs about Z GiB (…)".
+var agentNoSpaceRe = regexp.MustCompile(`has ([0-9.]+ GiB) free;.*needs about ([0-9.]+ GiB)`)
+
+// noSpaceLine renders the household's sentence for a space skip, "" when the attempt is not one.
+func noSpaceLine(errText string, msg func(key string, a ...interface{}) string) string {
+	if !strings.HasPrefix(errText, agentNoSpacePrefix) {
+		return ""
+	}
+	if m := agentNoSpaceRe.FindStringSubmatch(errText); m != nil {
+		return msg("backup.tier.no_space", m[2], m[1])
+	}
+	return msg("backup.tier.no_space_unknown")
 }
 
 // tierWindow is how old a tier's newest success may be and still count as current: its cadence plus
@@ -174,6 +197,7 @@ func buildTierViews(v *guestBackupView, tiers []agentapi.TierBackupState, cadenc
 		if a := t.LastAttempt; a != nil && !a.Success {
 			if ts, err := time.Parse(time.RFC3339, a.StartedAt); err == nil && (!tv.HasSuccess || ts.After(tv.SuccessAt)) {
 				tv.FailedAfter, tv.FailedAt = true, ts
+				tv.NoSpaceLine = noSpaceLine(a.Error, msg)
 			}
 		}
 		if !tv.NotSetUp && !tv.Current {