fix: comprehensive bug fixes and architecture restructuring

Phase 1 — Bug fixes (7 bugs):
- Bug 1: Pulsar mode data loss — always persist to SQLite regardless of mode
- Bug 2: PulsarSend closing TCP client — use independent resetPulsarProducer()
- Bug 3: Greedy regex — use non-greedy (?s)ZCZC.*?NNNN
- Bug 4: Data after NNNN discarded — keep remaining buffer data
- Bug 5: strings.Index > 0 boundary — use strings.Contains
- Bug 6: Variable shadowing in PulsarSend — use = not :=
- Bug 7: Accept failure nil panic — add continue + retry logic

Phase 2 — Architecture restructuring:
- Split utils/ into config/, serial/, telegram/, storage/, transport/
- Define Sender, Repository, Reader interfaces
- Introduce app/ layer with context.Context lifecycle
- Replace spinlock with sync.Mutex
- Unified Config struct replaces 15+ global vars

Phase 3 — Testing & tooling:
- telegram/parser_test.go (7 test cases)
- storage/store_test.go (5 test cases)
- transport/transport_test.go (4 test cases)
- Taskfile: add test, test-race, test-cover tasks
- Go version: 1.15 -> 1.21

go.sum

@@ -42,7 +42,6 @@ github.com/bgentry/speakeasy v0.1.0/go.mod h1:+zsyZBPWlz7T6j88CTgSN5bM796AkVf0kB
 github.com/bketelsen/crypt v0.0.3-0.20200106085610-5cbc8cc4026c/go.mod h1:MKsuJmJgSg28kpZDP6UIiPt0e0Oz0kqKNGyRaWEPv84=
 github.com/bmizerany/perks v0.0.0-20141205001514-d9a9656a3a4b/go.mod h1:ac9efd0D1fsDb3EJvhqgXRbFx7bs2wqZ10HQPeU8U/Q=
 github.com/boynton/repl v0.0.0-20170116235056-348863958e3e/go.mod h1:Crc/GCZ3NXDVCio7Yr0o+SSrytpcFhLmVCIzi0s49t4=
-github.com/cespare/xxhash v1.1.0 h1:a6HrQnmkObjyL+Gs60czilIUGqrzKutQD6XZog3p+ko=
 github.com/cespare/xxhash v1.1.0/go.mod h1:XrSqR1VqqWfGrhpAt58auRo0WTKS1nRRg3ghfAqPWnc=
 github.com/cespare/xxhash/v2 v2.1.1 h1:6MnRN8NT7+YBpUIWxHtefFZOKTAPgGjpQSxqLNn0+qY=
 github.com/cespare/xxhash/v2 v2.1.1/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
@@ -174,7 +173,6 @@ github.com/konsorten/go-windows-terminal-sequences v1.0.1 h1:mweAR1A6xJ3oS2pRaGi
 github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
 github.com/kr/fs v0.1.0/go.mod h1:FFnZGqtBN9Gxj7eW1uZ42v5BccTP0vu6NEaFoC2HwRg=
 github.com/kr/logfmt v0.0.0-20140226030751-b84e30acd515/go.mod h1:+0opPa2QZZtGFBFZlji/RkVcI2GknAs/DXo4wKdlNEc=
-github.com/kr/pretty v0.1.0 h1:L/CwN0zerZDmRFUapSPitk6f+Q3+0za1rQkzVuMiMFI=
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@@ -234,7 +232,6 @@ github.com/pelletier/go-toml v1.8.1/go.mod h1:T2/BmBdy8dvIRq1a/8aqjN41wvWlN4lrap
 github.com/pierrec/lz4 v2.0.5+incompatible h1:2xWsjqPFWcplujydGg4WmhC/6fZqK42wMM8aXeqhl0I=
 github.com/pierrec/lz4 v2.0.5+incompatible/go.mod h1:pdkljMzZIN41W+lC3N2tnIh5sFi+IEE17M5jbnwPHcY=
 github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
-github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
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@@ -475,7 +472,6 @@ google.golang.org/protobuf v1.23.0 h1:4MY060fB1DLGMB/7MBTLnwQUY6+F09GEiz6SsrNqyz
 google.golang.org/protobuf v1.23.0/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2l/sGQquU=
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-gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 h1:qIbj1fsPNlZgppZ+VLlY7N33q108Sa+fhmuc+sWQYwY=
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 gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 h1:YR8cESwS4TdDjEe65xsg0ogRM/Nc3DYOhEAlW+xobZo=
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