smol-toml: Quadratic-time parse() from parseKey rescanning to end of document on each key line
### Summary
`parse()` has a quadratic-time path in `parseKey`, reachable on default options with ordinary valid input. For every key line and table-header line, `parseKey` (dist/struct.js, lines 58 and 86) finds the dotted-key separator with `ctx.s.indexOf('.', ctx.p)`, where `ctx.s` is the whole document. When a key has no `.` ahead of it, that search runs all the way to the end of the input, and the result is then clamped back to the line terminator `endPtr` - so everything scanned past the current line is wasted. `parseKey` runs once per line, so a document of N dot-free keys costs O(n^2).
The most ordinary TOML shape triggers it: a flat
smol-toml: Denial of Service via malformed TOML documents
smol-toml is a small, fast, and correct TOML parser and serializer. Prior to 1.7.1, parse() can enter an infinite loop when a value inside an array or inline table is followed by a comment with no trailing newline. In src/util.ts, skipUntil() calls indexOfNewline(), receives -1 at the end of input, and resets the cursor to the beginning of the string instead of leaving the structure scan. The parser then hangs indefinitely and can consume a service's processing capacity when an application parses attacker-controlled TOML. This issue is fixed in version 1.7.1.
smol-toml: Denial of Service via TOML documents containing thousands of consecutive commented lines
### Summary
An attacker can send a maliciously crafted TOML to cause the parser to crash, because of a stack overflow caused by thousands of consecutive commented lines.
The library uses recursion internally while parsing to skip over commented lines, which can be exploited to crash an application that is processing arbitrary TOML documents.
### Proof of concept
```js
require("smol-toml").parse('# comment\n'.repeat(8000) + 'key = "value"')
```
### Impact
Applications which parse arbitrary TOML documents may suffer availability issues if they receive malicious input. If uncaught, the crash may cause the application itself to crash. The impa
smol-toml has a Denial of Service via malicious TOML document using deeply nested inline tables
### Summary
An attacker can send a maliciously crafted TOML to cause the parser to crash because of a stack overflow caused by a deeply nested inline structure. A similar problem occurs when attempting to stringify deeply nested objects.
The library does not limit the maximum exploration depth while parsing or producing TOML documents, nor does it offer a way to do so.
### Proof of concept
```js
require("smol-toml").parse("e=" + "{e=".repeat(9999) + "{}" + "}".repeat(9999))
```
### Impact
Applications which parse arbitrary TOML documents may suffer availability issues if they receive malicious input. If uncaught, the crash may cause the ap